measuring up

Humble, gracious, innovative, and respected are all words that describe the newest Dennis Gabor Award winner. SPIE Fellow Chandra Vikram, a research professor at the Center for Applied Optics at the University of Alabama in Huntsville (UAH), is the 2003 recipient of the award.

"I was elated when I learned about the Gabor Award going to Professor Vikram," says SPIE Fellow Rajpal S. Sirohi, director of the Indian Institute of Technology (IIT) Delhi. "He was my first PhD student at IIT Delhi, and we have written numerous papers together. IIT, at that time, was not a brand name. Certainly he is one of those who helped build this brand."

Chandra Vikram and his wife Bina.

The award is presented each year in recognition of outstanding accomplishments in electro-optical systems, with a focus on holographic imaging and metrology applications. Vikram's contributions come in a variety of areas, including speckle metrology, particle-field holography, multicolor holography, interferometry, and holographic vibration analysis. "It has been very joyous to be constantly in touch with several areas of active research," Vikram says.

The Dennis Gabor Award isn't the only distinction Vikram has garnered. He received the University of Alabama in Huntsville Foundation Award for Research and Creative Achievement in 1997 and a certificate of recognition from the NASA Inventions and Contributions Board in 1994.

But one award stands out among the rest. Out of about 25,000 IIT Delhi graduates, only 23 have been honored with the IIT Delhi Distinguished Alumni Award, and Vikram became one of the few in 2002. He is very honored to have received the award and says of the other winners, "They are very distinguished. I'm just lucky to be in their company."

"Chandra is a very humble man, but his humility masks a vast amount of experimental knowledge," says SPIE Fellow Akhlesh Lakhtakia of the Pennsylvania State University (Penn State; University Park, PA). Vikram began accruing this experimental knowledge in his home country of India. He earned his BSc at Agra University, then pursued his MSc, MTech, and PhD degrees at IIT.

"The optics degree program at IIT Delhi was very new and rare even internationally," Vikram says. "The faculty projected optics as a futuristic subject, and frequent visits by internationally known professors somewhat glamorized the subject and surely attracted me to the field."

A few years after completing his education, Vikram took a research job at Penn State and moved up to senior research associate in the Materials Research Laboratory and the Applied Research Laboratory within five years. In 1989, he came to the Center for Applied Optics at UAH.

Bina, son Tushar, and Chandra at the SPIE 2001 Annual Meeting.

Known for his pioneering work on correcting significant measurement errors caused by the diffraction halo in speckle metrology in the early 1980s, Vikram more recently continued his work with speckle interferometry in the nondestructive measurement of residual stresses. The method involves measuring deformations caused by local heating by a laser. "The deformations measured are related to the stresses in a very complex but deterministic manner," he explains.

"Residual stress is a very fundamental problem—structures break, bridges break. If containers where they put nuclear material break, it's a disaster, and they cannot keep on replacing the container because it is very costly. So that is why the whole field of residual stresses has been very important for a long time. But this idea of locally heating it, not melting, but heating a little bit, then relieving some stress, and from that inferring how much stress is there, that's unique and new."

Phase shifting interferometry and multicolor holography are two areas that Vikram has found success with as well. The former resulted in an algorithm adopted by the commercial interferometric system PhaseCam (4D Technology Corp.; Tucson, AZ). As for multicolor holography, he was the first to notice the critical fringe counting needs in two-color holographic interferometry. The observation yielded several technological developments in heat and mass transfer problems and resulted in the certificate of recognition from NASA.

Particle-field holography may be his best-known work, though. "Chandra is the master of holographic testing. He has explored such large numbers of different testing configurations and has exhaustively developed new applications," says SPIE Fellow Russell A. Chipman, University of Arizona (Tucson, AZ).

"Generally, resolution and depth of field in photography work against each other," explains Vikram. "That is why sharp pictures yield blurred background scenes. However, in scientific applications, like studying cavitations in a water tunnel, you need to study bubbles to a few micrometers' resolution not only in a sharp plane but also across the whole depth." While at Penn State, he applied this form of holography extensively and also developed rigorous aberration theory and non-image plane analysis of such holograms.

Another interesting aspect of his work was a project involving the nondestructive evaluation of eggshell strength. One day, Vikram ran into a fellow Penn State professor at a grocery store. "He was doing some genetic work involving increasing eggshell strength, as loss during transportation was a serious issue. His research did not have any procedure to measure the shell strength as such and breaking changed the very properties they were measuring by conventional tools. I told him holographic interferometry could do the job without such destruction." They started on the problem the next day, and their cooperation resulted in a paper honored by the Poultry Science Association of America.

Some of his most recent work, though, includes inventing methods for faithful analysis of particle image velocimetry in a complex fluid scenario. Other research is focused on automated analysis of particle holograms. "Another problem I am working on is measurement of thermal expansions of solids in cryogenic temperatures. Several years ago, I devised non-interferometric methods for ultra-low thermal expansion measurements. However, this time I am attempting [this work] for real applications in a NASA cryogenic chamber."

Vikram is a fellow of the Optical Society of America and a life member of the Optical Society of India. He was an editor of the SPIE Milestone volume Selected Papers on Holographic Particle Diagnostics (1990) and wrote Particle Field Holography, published in 1992 by Cambridge University Press. He has also penned 140-plus papers in refereed journals and numerous other book chapters and papers. In addition, Vikram has been a member of the editorial board of the Asian Journal of Physics since 1994 and is currently a member of the advisory board to the department of physics and applied optics at the Rose-Hulman Institute of Technology (Terre Haute, IN).

The Vikram family (from left), Tushar, Bina, Chandra, and Preeti.

"I have been married to my wonderful wife Bina for 28 years. Daughter Preeti completed a BS (MIS) from my university. She is working at local Intergraph Corporation and also taking part-time courses at our university aiming for her MS. Son Tushar is a senior at Georgia Institute of Technology (electrical engineering) and is a student member of SPIE and OSA."

Vikram stresses that he has not done all this work alone. "I would like to thank my teachers and fellow students at the Indian Institute of Technology, co-workers at The Pennsylvania State University and the University of Alabama in Huntsville, and professional colleagues at NASA Marshall Space Science Center, MetroLaser, Inc., Westinghouse Savannah River Company, etc.; they all have a serious role in my accomplishments," he says. Humble as always.