Samuel E. Blum (1920–2013): The Chemist Who Revolutionized Vision
While the name Samuel E. Blum may not be a household word, his work has touched the lives of millions. A physical chemist whose career spanned the golden age of industrial research at IBM, Blum was a co-inventor of the application of the excimer laser for medical purposes—the foundational technology that made LASIK and PRK eye surgeries possible. His transition from studying semiconductors to biological tissue represents one of the most significant "pivot points" in 20th-century applied science.
1. Biography: From New Jersey to the Frontiers of Physics
Samuel Emil Blum was born on August 28, 1920, in New Brunswick, New Jersey. His academic journey began at Rutgers University, where he earned his B.S. in Chemistry in 1942. His studies were interrupted by World War II, during which he served in the U.S. Army, applying his chemical expertise to metallurgical research for the military.
Following the war, Blum returned to Rutgers, completing his Ph.D. in Physical Chemistry in 1950. After a brief four-year stint at the Battelle Memorial Institute in Ohio, he joined the IBM Thomas J. Watson Research Center in Yorktown Heights, New York, in 1954. He remained at IBM for the rest of his career, retiring in 1990 as a member of the prestigious Senior Technical Staff.
2. Major Contributions: The "Cool" Cut
Blum’s early career focused on semiconductor materials, specifically III-V compounds like gallium arsenide. His work in crystal growth and vapor-phase epitaxy was instrumental in the development of early light-emitting diodes (LEDs) and semiconductor lasers.
However, his most profound contribution came in the early 1980s. Working alongside physicist James J. Wynne and chemist Rangaswamy Srinivasan, Blum explored the potential of the Argon-Fluoride (ArF) excimer laser. Unlike infrared lasers, which cut by burning or melting material (causing thermal damage to surrounding areas), the excimer laser emits ultraviolet light at a wavelength of 193 nanometers.
Blum and his team discovered Ablative Photodecomposition (APD). They found that the high-energy photons of the excimer laser could break the molecular bonds of organic polymers—and biological tissue—with such precision and speed that the material was vaporized without heating the surrounding area. This "cold" laser allowed for microscopic precision, removing layers of tissue one-tenth the thickness of a human hair without scarring.
3. Notable Publications and Patents
Blum’s legacy is documented less in textbooks and more in the patents that transformed modern medicine.
- U.S. Patent 4,784,135 (1988): Far Ultraviolet Surgical Irradiation. This is the seminal patent for the trio, describing the use of the excimer laser to de-bulk or shape biological tissue.
- Ablative Photodecomposition of Biological Specimens (1983): Published in Science (co-authored with Srinivasan and Wynne), this paper provided the scientific community with the first rigorous proof that UV lasers could precisely etch tissue without thermal necrosis.
- Radiative Recombination in GaP (1960s/70s): Blum authored numerous papers on the chemistry of semiconductors that laid the groundwork for modern optoelectronics.
4. Awards and Recognition
The significance of Blum’s work was recognized late in his life, as the long-term impact of LASIK became undeniable.
- National Medal of Technology and Innovation (2011): Awarded by President Barack Obama, this is the highest honor the United States bestows on inventors.
- National Inventors Hall of Fame (2002): Inducted alongside Wynne and Srinivasan for the discovery of excimer laser surgery.
- R.W. Wood Prize (2004): Awarded by the Optical Society of America for the discovery of pulsed ultraviolet laser surgery.
- Rank Prize in Optoelectronics (2010): A prestigious international award recognizing the practical application of light-based technologies.
5. Impact and Legacy
The impact of Samuel Blum’s work is staggering in its scale. Before his discovery, correcting refractive vision errors required physical blades (RK surgery) which were often imprecise and prone to complications.
Today, over 30 million people worldwide have undergone LASIK or PRK procedures. Blum’s discovery of APD didn't just create a new industry; it redefined the relationship between surgery and technology. The excimer laser is now also used in the treatment of skin conditions and in the manufacturing of microchips, bringing Blum’s career full circle back to his semiconductor roots.
6. Collaborations: The IBM "Dream Team"
Blum was a quintessential collaborator. His partnership with Rangaswamy Srinivasan and James J. Wynne is often cited as a perfect example of interdisciplinary research.
- Srinivasan brought the expertise in polymer chemistry.
- Wynne provided the physics and laser optics knowledge.
- Blum bridged the gap with his deep understanding of physical chemistry and material properties.
The trio worked in an environment at IBM Research that encouraged "blue-sky" thinking, allowing them to experiment with a laser that was originally intended for etching circuits into silicon chips, not repairing human eyes.
7. Lesser-Known Facts: The Thanksgiving Turkey
The breakthrough moment for the excimer laser's medical application is one of the most famous anecdotes in the history of IBM Research.
On the day after Thanksgiving in 1981, Srinivasan brought his leftovers to the lab—specifically, a turkey bone. The team used the excimer laser to etch a clean, precise line into the cartilage of the bone. When they examined it under a microscope, they saw that the edges were perfectly smooth, with no signs of burning. This "turkey bone experiment" was the "Eureka" moment that proved the laser could be used on biological tissue without destroying the living cells nearby.
Blum was also known for his humility. When asked about the millions of people who could see clearly because of his work, he often demurred, crediting the
"freedom to explore"that he enjoyed during his decades at IBM. He passed away on January 9, 2013, leaving behind a world that literally sees more clearly because of his curiosity.