Colored Light Therapy

NEW DEVELOPMENTS IN COLOR THERAPY

Acupuncture Meridians Facilitate the Body’s Absorption of Light

by: Anna Cocilovo, PA-C, Dipl. Ac. & Ron Rosen, OMD, FNAAOM

copyright, February 1999

ACUPUNCTURE OVERVIEW

Acupuncture is well known worldwide as an effective treatment to facilitate healing. The traditional theory of acupuncture and Oriental Medicine is a complex and coherent one, unifying all body systems, and the physical with the mental/emotional. Scientific studies verifying the affects of acupuncture abound, although scientific explanation for the mechanism of action remains elusive. Popular interest in acupuncture is growing, paricularly spurred by the National Institue of Health Office of Alternative Medicine, and the positive report from the October 1998 NIH consensus panel. Traditional theory states that Qi is the animating force behind life, the cosmic forces of Nature, and is the root of all things. If one stays in touch with Qi, ones life will be healthy in all its phases.

Traditional acupuncturists apply the simple and yet complex theories of Qi to treat a wide range of ailments from pain to chronic illness and functional problems, through insertion of very fine needles at the acupuncture points thereby creating a disturbance in the energetic field. Stimulation of acupuncture points, being more electrically conductive, produces a polarity or electrical gradient, facilitating electromagnetic conduction, or movement of Qi.

HISTORY OF COLORED LIGHT THERAPY

Just as acupuncture is a very old system of medicine being rediscovered, so is light therapy, or phototherapy, a “new old” system, which promises to come further into the “limelight”. Phototherapy was practiced in ancient Egypt, Greece, China, and India. The Egyptians utilized sunlight as well as color for healing. In the past 120 years, great strides have been made in research and development of colored light as well as full spectrum light therapy. In 1876 Augustus Pleasanton stimulated the glands, organs, and nervous system with blue light. In 1877 Seth Pancoast used red and blue light to balance the autonomic nervous system. In 1878 Dr. Edwin Babbitt published The Principles of Light and Color. He elucidated a system for applying colored light to the body, and used solar elixirs, which are colored bottles containing water charged by the sun. He was able to successfully treat many stubborn medical conditions, unresponsive to conventional treatments of the time.

Dinshah Ghadiali, PhD, MD (India), an American who immigrated from India, was highly influenced and inspired by Babbitt’s work. In 1897, the course of his life and views on medicine were forever changed when he saved the life of a woman dying from intractable dysentery. Under conventional treatment she continued to have 100 diarrheal stools per day. As a last resort, Dinshah proceeded to shine indigo light on the patient’s body. By the end of the first day, the number of evacuations was reduced to 10. By the third day she was out of bed.

By 1920, after 23 years of research and clinical observation, Dinshah, as he came to be known in America, had refined a sophisticated system of color phototherapy he called Spectro-Chrome. Influenced by a strong background in mathematics and physics, he reasoned that the physiologic effects of individual colors would correspond with the action of the mineral which exhibited that color on spectometry. He thereby determined in detail, specific “attributes” of the colors, i.e., the specific effects of the colors on the physiology. He further determined precise and predictable formulations of applying colored light directly to the body for the gamut of physical injury and illness. He was the first to develop a system of healing utilizing all the colors of the spectrum: red, orange, yellow, lemon, green, turquoise, blue, indigo, violet plus purple, magenta and scarlet.

Spectro-Chrome is based on three principles: 1) that the human body responds to light 2) colors relate to physiologic function and 3) color tonation (broadcasting specific colors to the body surface) aids bodily function. Dr. Kate Baldwin, a highly respected physician, AMA member, and chief surgeon of the Women’s Hospital of Philadelphia, became a student, practitioner, and strong proponent of Dinshah’s techniques both in her private practice, and within the hospital setting. Case histories abound of the successful treatment with Spectro-Chrome. Unfortunately then, as now, political forces of high tech, elitist, expensive, profit motivated medicine embarked on a crusade to discredit and repress Dinshah’s simple but effective low technology healing system. Dinshah was subjected to decades of indictments, court battles, fines and arrests which in 1947 culminated in being forced to burn his personal collection of all printed material (valued at $250,000) pertaining to colored light therapy. Only a single copy of personal notes was spared. Six years later, after completing probation, Dinshah persisted, restructuring his institute for educational purposes only, and making no claims as to the therapeutic value of projected colored light. Although Dinshah lived out his life under these permanent injunctions secured by the FDA, his system of color therapy, Spectro-Chrome, survived and is today, 30 years after his death in 1966, beginning to enjoy a renaissance. Dinshah, though little recognized to this day, is without a doubt one of this century’s great luminaries.

Internationally, alternative approaches to healing did not meet with such resistance. Dr. Niels Finsen, a Danish physician, pioneered light therapy in the 1890’s. He noticed that tubercular skin lesions were much more common during the long dark winters, but rare in summer. In 1892 he began treating this condition, lupus vulgaris, with light. Later he would use red light to prevent scar formation from smallpox, and eventually established a light institute for the treatment of tuberculosis. His work was so successful in the treatment of skin tuberculosis with ultraviolet light, that he was awarded the Nobel Prize in 1903.

PHYSICS OF COLORED PHOTOTHERAPY

Dr.’s Babbit, Pancoast, Pleasanton, Baldwin, Finsen and Dinshah provide us with ample empirical evidence of the value of colored light in medicine. The scientific explanation for this rests in quantum physics and color theory: the photoelectric effect first discovered by Hertz, and the theory of light elucidated by Einstein. By the photoelectric effect, when light strikes any material substance, electrons are discharged, creating a current. In other words, light interacts with matter as the energy of the light is transferred to electrons.

In 1905, Einstein offered an explanation for this phenomenon with his Corpuscular Theory of Light, for which he was awarded his only Nobel Prize. He proposed that light is composed of corpuscular units called photons. A photon is the smallest unit of light and has a dual nature, being both particle and wave at the same time. A photon travels at the speed of light and its energy is related to the frequency of radiation. The energy of the photon is transmitted to the electron. The shorter the waves of light the greater the energy of the photon, which results in stronger acceleration when that energy is transferred to the electron. The intensity of the light determines how many photons strike a given surface, and likewise, how many electrons are discharged. The higher the intensity, the greater the quantity of photons and the greater the number of electrons activated. The wave theory of light, held prior to this, was unable to account for the photoelectric effect.

COLOR THEORY

Color is frequency. Specifically, color is frequency within the visible spectrum of light, which composes a very small band of the total electromagnetic spectrum, from violet at 400 nanometers (higher energy photon) through red at 780 nanometers (lower energy photon). Beyond violet in increasingly shorter wavelengths, are ultraviolet light, x-rays, and gamma radiation which contain tremendous amounts of energy. Infrared and radio waves are longer wavelengths outside the red end, with very little energy.

Each color of the spectrum is composed of a band of frequencies. Therapeutic application of light to the body is accomplished by applying a single monochromatic wavelength within that band. It has been said that when the body is healthy, it may be able to filter out from white light or sunlight, whatever color frequency it needs. But if a person’s health is compromised the necessary color must be supplied. As stated by the photoelectric effect, the frequency of radiation determines the energy of the electrons emitted. This supports the rationale behind Dinshah’s empiric system of color attributes; individual frequencies have specific effects.

BRIDGING COLOR THERAPY AND ACUPUNCTURE

There is much work going on these days in the use of full spectrum and colored light for mind/body healing. There is no doubt that light is necessary for health, and even life itself. The term “malillumination syndrome” has been coined to explain the vegetative effects on health from being undernourished by light. We now understand that individual sensitivity to diminished full spectrum light underlies seasonal affective disorder. Dr. Dan Oren, at the National Institutes of Mental Health, has brought colored light into this equation, finding that green light is more effective than red in the treatment of S.A.D.. Colored light therapy through the eyes, and applied to the body, is being utilized in the fields of psychology, optometry, chiropractic, medicine, and acupuncture.

Colored light has a particular ability to balance the autonomic nervous system, which is crucial in most chronic and functional disorders as it regulates all of the automatic processes of the human body: breathing, the beating of the heart, the functioning of the digestive tract, the stress response. Light as an environmental stimulant, is second only to food in its impact on controlling bodily functions. Interestingly, light through the eyes reaches not only to the visual centers of the brain, but also the hypothalamus. The hypothalamus is the brain’s brain. It organizes information from our external and internal environments, initiates the stress response, regulates immune function, reproduction, thirst, hunger, temperature, emotions, and sleep patterns. It houses the body’s biological clock, controls most of the functions of the pituitary gland, and controls the autonomic nervous system. Light from the hypothalamus is then sent to the pineal gland, the body’s light meter and only gland in the body not controlled by higher neurological centers. It transforms retinally perceived light waves into neuronal impulses and hormonal messages through melatonin production. Melatonin is both created and released by the pineal gland in response to light and darkness. The pineal gland and melatonin are our physiologic and hormonal connection to our environment and the universe. In Oriental medicine, we say that the human being is created when the Qi (energy) of Heaven and the Qi of Earth come together. I postulate that the Qi of Heaven continues to enter the formed human body through the pineal organ in the form of light.

So we are just starting to recognize, investigate, and understand the integral and profound role light plays in regulating and maintaining health in the body/mind. Its application to acupuncture is natural.

Russian researchers at the Institute for Clinical and Experimental Medicine, have shown that light applied to the human skin penetrates the body between 2 and 30mm, depending on the color frequency (another explanation for the individual color attributes). They were able to track the light by magnifying it with a photomultiplier, and measuring it with a photometric unit. The researchers found that only certain areas of the body were able to transfer light beneath the surface, and that these areas corresponded to the acupuncture points. Not only that, the light was conducted within the body along the acupuncture meridians. Although light penetration may be superficial, deeper physiological processes may be stimulated. It seems that the meridians are a light transferal system in the body somewhat like optical fiber. Just as light through fiber optics is being used to store information in computers, and transfer it almost instantly around the globe, perhaps the meridian system as a conductor of light provides the coherent unified theory of a subtle energy information system within the body. This could be the missing link, uniting materialistic medicine with subtle energy healing modalities, and bridge the gap between physics and metaphysics. The transmission of photons, which you recall, travel at the speed of light within the meridian system, may be a more fundamental aspect of Qi than electromagnetic energy which deals with relatively inert ions or electrons.

Dr. Tiina Karu, Ph.D., with the Laser Technology Center in Russia, and affiliated with the University of California at Berkeley, has researched the effects of light on the cell since the 1980’s. She has found that there are photo-receptors at the molecular – cellular level which, when triggered, activate a number of biological reactions: DNA / RNA synthesis, increase cAMP levels, protein and collagen synthesis, and cellular proliferation. The result is rapid regeneration, normalization and healing of damaged cellular tissue. In essence, light is a trigger for the rearrangement of cellular metabolism.

Although light penetration may be superficial, deeper physiological processes may be stimulated. Laser light therapy has been shown to decrease healing time of wounds and ulcers, decrease edema, and facilitate bone remineralization.

COHERENT vs. INCOHERENT LIGHT

Light therapy and acupuncture have most popularly interfaced through the use of laser technology. Laser is an acronym for light amplification by stimulated emission of radiation. Laser is simply light which is coherent. Coherent light beams have minimum divergence and maximum parallelism over distance. This is as opposed to incoherent light which is regular visible light beams which scatter. Hot lasers are used in surgery to cut, cauterize and destroy tissues. Lower power lasers, referred to as “soft” or “cold” lasers, are used in place of acupuncture (“needleless acupuncture”) in clinics, research facilities, and hospitals around the world to produce therapeutic effects through photobiostimulation. Soft lasers are classified by the FDA as Class III, nonsignificant risk medical devices for investigational purposes only.

Surprising new research from Cornell University also supports this supposition that the body absorbs light through the skin, and that this light has physiological action. Chronobiologist Scott Campbell found that the biological clock could be reset by shining light on the back of the knee. Prior to this it was believed that the light had to be transmitted through the eyes. This has important implications for the treatment of seasonal affective disorder and sleep disorders linked to aberrations in circadian rhythm.

There is a vast amount of research documenting the biological responses and efficacy of laser biostimulation, much of which is applicable to incoherent light. It has a homeostatic effect: promoting skin regeneration or reducing scar tissue, decreasing pain or promoting enhanced sensitivity in numb areas, reducing swelling and irritation or improving circulation and enhancing the immune system. However, soft laser treatment is not without risk. It can be overused in intensity and duration. It is harmful if it comes in contact with the eyes. There is also thought that if used for a prolonged period, it can damage acupuncture points, leading to reduced effectiveness, as taught at acupuncture seminars at the University of Washington.

In all the excitement over laser, sight has been lost of the prior work done with incoherent light. Dr. Karu (noted above) contends that coherent light is not necessary, that incoherent light is equally effective at producing clinical results. Furthermore, she found that coherent light is converted to incoherent light in the body. The exact effect depends on the wavelength, dose and intensity. In Israel, medical doctors utilize incoherent light transmitted by light emitting diodes (LED’s) in the practice of neurology, dentistry, dermatology, physiotherapy, and in cosmetic applications to promote collagen and elastin formation.

As often happens in life, we became intrigued with the use of colored light in conjunction with acupuncture by circumstance. A friend introduced us to a penlight device for applying colored light to acupuncture points, but the device was clumsy and the light was not intense enough. Shortly after, we became acquainted with the work of the noted French physician, Dr. Paul Nogier, who is most well known for developing auricular acupuncture and the Vascular Autonomic Signal. He had first experimented with the autonomic nerve wreath in the iris to help establish the light connection to the body’s sympathetic nervous system. Nogier and his colleague Dr. Rene Bourdiol, co-authored a book on the subject in 1975 (Treatise on Iridodiagnosis). Later, Bourdiol, in his book Auriculo-Somatology, described how Nogier used colored and pulsed light on the ear to affect the body’s energy systems. This information, along with the knowledge of Dinshah’s work peaked my interest in photostimulation of acupuncture points.

PHOTON STIMULATOR

The device we have been using for applying colored light to acupuncture points is called the Photon Stimulator. It can be used on its own, or in conjunction with standard acupuncture treatment. Its design seems to address many of the problems of prior colored light devices, making it both effective and user friendly. The PS is a plug-in unit comprised of a xenon plasma gas tube which provides full spectrum light. The light is pulsed and transmitted through high grade optic fiber to the handpiece with a precise tip where the light is focused. The combined aspects of being a plug-in unit vs. battery powered, the high wattage xenon bulb, and the optic fiber which transmits 99.4% of the light to the tip, insure high intensity stimulation of the skin. As previously stated, higher intensity means a greater number of electrons discharged. In practice, this translates to shorter treatment times.

Some of the other problems we encountered in other machines were the bulky nature of the applicator, and lack of color specificity. Both of these issues seem to be adequately addressed. The design of the lightweight handpiece facilitates precise location and treatment of either points or areas on the body, or in the ear where precision is a must. The PS utilizes color gel filters manufactured by Roscolene, the world’s top photographic filter company. Roscolene gel filters minimize dye migration and pigment fading. They are the same precise frequencies researched for over 50 years by Dinshah. Each color gel filter comes in a 35mm slide casing, making it convenient and quick to change colors by dropping them in and out of a slot.

Our experience, and those of both colleagues and patients utilizing the PS have shown that very short treatment times are effective. Only 15 – 30 seconds are necessary at each point. The light is pulsed, reinforcing the stimulation. The flicker rate is adjustable between 0 -10 hertz. We usually set it around 5 hz. This seems to feel best and has some scientific basis. Nogier found that 5 hz is optimal in facilitating balance within the autonomic nervous system, creating a window of opportunity wherein organ systems can be accessed and affected. Dr. Norm Shealy, MD, a holistic physician, researcher, and founder of the American Holistic Medical Association, speculates that light works through the connective tissue, affecting cellular memory and output of neurotransmitters. He uses 7.8 hz which is theoretically the background human frequency, based on the Schumann resonance, the frequency of the earth.

CASE HISTORIES

The following are case histories from my experience, and the experience of colleagues utilizing the Photon Stimulator for photobiostimulation.

Chronic Wrist Pain and Immobility

A 28 year old woman was suffering from chronic pain and limited range of motion of her right wrist subsequent to a fracture and internal fixation (surgical intervention) about 6 months previous. Curiously, she asked me what was the meaning of a point in the right ear located in the area called the scaphoid fossa. It corresponded with the wrist point in the ear. She had recently had an irresistible urge to pierce her ear there, and had intuitively treated herself! Because it was a chronic problem, first we applied lemon to master points in the ear for pain control – Point 0, Shenmen, and Thalamus. Then purple was applied to ear wrist point. Immediately, she had less pain and improved range of motion.

Asthma

An 11 year old boy with chronic asthma developed an asthma attack while playing with my son at our house. Since he was not in acute distress, I offered the color treatment and he agreed. He had an inhaler if we needed to resort to that. Since he was in the middle of an attack, we needed to sedate the lungs, and rev up the adrenals. Purple was applied to auricular Lung, and body points Lung 1, and CV 17 in center of the chest. Then scarlet was applied to auricular kidney and adrenal points, and body point Kidney 3. He calmed down considerably within 5 minutes, and was totally better within 10 minutes. He commented that when this happens and he uses his inhaler, he continues to cough throughout the day, but he was symptom free and felt great after the auricular light treatment.

Wound Care

A young boy suffered a skin abrasion on his leg from a lacrosse accident. The wound was infected and not healing quickly, but did not show signs of cellulitis. One treatment was given with green light over the affected area. It was quite remarkable as visible healing was apparent immediately. The redness went out of the skin right before our eyes. We then went on with his regular acupuncture treatment for migraine headaches, and the wound healed well without further incident.

Cellulitis

A 40 year old woman with cellulitis was not responding to antibiotics. Her doctor recommended hospitalization for IV antibiotic treatment. As a last resort, she asked for help from her acupuncturist. We treated the local area three times that day, and once the next day alternating green and blue light over the local area. The inflammation came down to a point where the infection was manageable with oral antibiotics, and hospitalization was avoided.

Anosmia

A 52 year old woman had totally lost her sense of taste and smell for one year subsequent to an injury of the olfactory nerve suffered in a motor vehicle accident. She consulted an acupuncturist, but had no improvement. She then consulted our office. We had had some success with similar conditions in the past using scalp, auricular, and local treatment. this time, in addition, we used red light on scalp and ear points. Within 7 treatments, she got results which took 18 – 20 treatments to get without the help of the light. She regained 70-80% of her prior sense of taste and smell.

Tic Douloureux

A 43 Year old MS patient had not been able to eat solid food or speak normally for 6 weeks secondary to severe facial neuralgia. Acupuncture was done on scalp and ear points, but local needling was not possible because of the extreme sensitivity. Purple light was applied to local facial points. After the third treatment, she was able to eat a whole meal.

Chronic Pain, a Patient Testimonial

“Possibly the most noteworthy treatment that I have had that has truly changed my entire quality of life has been the complete elimination of pain brought about by the Multiple Sclerosis. The entire right side of my body suffered from deep pains where my muscles and tendons just plain hurt. I felt like I had played an entire football game getting hit exclusively on the right side of my body. Talking to other people suffering from MS, they also share similar stories of their pains. Well, Dr. Chernoff talked to me about a treatment she felt confident would work. The treatment is Photon Stimulator Color Therapy which I like because it is completely non-intrusive to the body. I was skeptical at first but not 15 minutes following the treatment I looked at my wife and said, `it’s gone, the pain is totally gone’. I have felt no pain since the color therapy and that has been more than three months now.” M.M., Albuquerque, NM, 1998.

DISCUSSION

We have been using colored light therapy in our practices for two years. As with any healing system or modality, light therapy is neither a magic bullet nor a cure all. But it has clearly shown itself to be an invaluable asset. We use it in combination with standard acupuncture treatment, or rely on it for the sole treatment. It is wonderful to use with children, and with patients who are needle phobic or are hypersensitive. Some patients use it at home on themselves and their family, as it is safe and simple to apply.

The Dinshah system of color therapy dovetails nicely with traditional Oriental medicine theory, relating colors to the internal organs and meridian system. Yellow builds the pancreas and improves digestion, red is hot and stimulating, magenta strengthens the kidneys and adrenals. the warm colors (red, orange, yellow, lemon, scarlet) strengthen and tonify, while the cool colors (turquoise, blue, indigo, violet, purple) sedate, calm, ease pain and inflammation. The Photon Stimulator includes a manual which has sample treatments and the basics of the Dinshah color system so one can start using it right away. Other sources are cited for those who want to delve more deeply.

What has been most notable from the beginning of this exploration, is the rapidity with which healing can take place with something as seemingly simple and noninvasive as light. It compels one to stop and reconsider what our true nature is – that we are in a very literal sense light beings as ancient mystical teachings profess. There is new scientific evidence to support this. Fritz Popp, a German physicist and chemist, published research in the mid 1980’s documenting that the cells of all living things radiate light. He further hypothesized that photons are carriers of information in living systems. Dr. G.J. Hyland, of the Department of Physics at the University of Warwick, UK, has recently (1998) published research also demonstrating that living systems spontaneously emit biophotons. Findings of this type seem natural and expected to those who accept the energetic nature of reality. At the same time, it validates the concept of Qi, which has been such a stumbling block to the acceptance of Chinese medicine in the West.

The efficacy of this particular light therapy device has also led us to reconsider the nature of light. Perhaps not all light is created equal. Dr. John Ott’s work on the benefits of full spectrum light, and conversely, the deleterious effects of fluorescent lighting on both physical and mental health and well being is well documented and prolific. Psychologist Dr. Warren Hathaway investigated the effects of full spectrum lighting on the performance of 300 ten to twelve year-olds in the Canadian school system. Compared to those exposed to cool white fluorescent or sodium vapor lamps, the full spectrum group excelled physically and academically. They had fewer sick days, greater gains in height and weight, and made greater academic progress. His findings were reported at the 1992 meeting of the American Psychological Association.

This research indicates that light has positive or negative effects depending on which frequencies of the electromagnetic spectrum are present. Peter Bros, in his book, Light, goes a step further. He postulates that light is actually made of what gives it off, by emission of electrons from the source. So the light emitted from a full spectrum fluorescent bulb would be different in nature from the full spectrum light emitted by one of the noble plasma gases, as it is in the case of the Photon Stimulator, and certainly different from that emitted by an incandescent bulb. Xenon, being a nonreactive gas, has no deficit of electrons, and thus plenty available for creating the light frequencies. Many elements, including the more solid ones (tungsten filaments?) are loathe to give up electrons. Perhaps, by accident, this explains the overall overall effectiveness, and sometimes amazing results which have been observed. It is to be noted that the original Rife device employed radiation from generated from another noble gas, argon.

Therapeutic use of colored light is in its infancy. There are more questions than answers. The field is wide open for research which, I am sure will, secure the invaluable role of light in medicine of the 21st century.

Ron Rosen, OMD, FNAAOM, has been in Oriental medicine practice, which he learned through lineage tradition, for over thirty years. He is also a martial artist of over 40 years experience. He practices in Denver, Colorado, and conducts classes for Maya barefoot doctors in Guatemala. Ron also teaches seminars nationally on many subjects including color therapy and injury medicine.

Anna Cocilovo, PA-C, Dipl.Ac., has been a physician assistant for 20 years, and a practicing acupuncturist for 11, with experience in allopathic medicine, traditional Oriental medicine, research and integrative medicine. She received her acupuncture training at Kototama Institute in Santa Fe, New Mexico. She practices acupuncture and complementary medicine in Prescott, Arizona, and teaches seminars integrating colored light therapy into acupuncture practices.

Bibliography

1. Dinshah, Darius: *Let There Be Light. Dinshah Health Society, Malaga, NJ, 1996.

2. Breiling, Brian (ed): *Light Years Ahead: The Illustrated Guide to Full Spectrum and Colored Light in Mindbody Healing. Celestial Arts, Berkeley, CA, 1996.

3. Mandel, Peter: *Practical Compendium of Colorpuncture. Ditton Energetik, Bruchsal, Germany, 1986.

4. Douglass, William Campbell: *The Healing Power of Light. Second Opinion Publishing, Inc., Atlanta, GA, 1996.

5. McWilliams, Charles: *The Revolutionary Photobiotics: Quantum Energy Dieting & Lifestyle Through Color. ProMotion Publishing, San Diego, CA, 1995.

6. Bourdiol, Rene J: *Auriculosomatology. Maisonneuve, Paris, France, 1983.

7. Liberman, Jacob: *Light: Medicine of the Future. Bear & Company Publishing, Santa Fe, NM, 1991.

8. Pankratov, Sergei: Meridians Conduct Light. *Raum and Zeit; Germany:1991. (In German)

9. Brown, Thomas J: Some Observations on the Relationship Between Light and Electricity. *Borderlands; Second Quarter, 1996.

10. Cromer, Alan: *Physics in Science and Industry. McGraw-Hill, New York, 1980.

11. Pais, Abraham: *The Science and Life Albert Einstein. Oxford University Press, New York, 1982.

12. Clark, Ronald W: *Einstein, The Life and Times. World Publishing Company, New York, 1971.

13. Bragg, William: *The Universe Of Light. Dover Publications, New York, 1959.

14. Cutnell and Johnson: *Physics. 2nd Ed. Wiley, New York, 1992.

15. Bros, Peter. Light. Financial Book Partners, 1996.