Quantum Optics and Photon Physics
Dr.(Ms) Ranjana Mehrotra
Primary Standard of Optical Radiation in the form of Blackbody: Spectral Radiance Measurement Facility
Source based primary standard of spectral radiance in the form of a variable temperature blackbody has been established. This blackbody works in the temperature range of 1800K ֠3200K with temperature stability of Ѡ0.2K. Its emissivity is 0.999, and exhibits radiance uniformity within 0.1%, in the wavelength range 0.2 ֭-2.5 ֭. The uncertainty in spectral radiance measurement using this blackbody is 0.3-0.5% in the wavelength range 0.2 ֭-0.4 ֭, and 0.1-0.3% in the wavelength range 0.4 ֭-2.5 ֭, respectively.
Experimental setup for absolute quantum efficiency measurement
A facility for absolute quantum efficiency measurement of photo-detectors using SPDC is established at NPL India. Experimental setup for SPDC is shown in the figure. KDP, BBO and lithium iodate (LiIO3) nonlinear crystals, respectively are used to create a pair of entangled photons, using high power CW Ar+ ion laser. Entangled photons are detected using avalanche photodiodes and their correlation is studied using photon correlator.
Experimental setup for absolute quantum efficiency (810 nm) measurement
Facility for generation of polarization entangled photon pairs at 810 nm based on SPDC, for the basic quantum optical studies and their application in quantum information was also established.
Infrared spectroscopic studies for tumor diagnosis
- The aim is to establish definite infrared markers that will distinguish malignant tissues from the normal ones and to use them for detection of malignancy.
- To develop IR spectral techniques for the quantification of proteins and enzymes which become active during malignant transformation of cells
|The spectra of biomolecules are highly specific, IR spectral changes can therefore be used to identify changes occurring in the biomolecules in conditions like malignancy|
Vibrational spectroscopic studies on DNA-Drug Interaction
- Understanding of the mechanism by which drugs interact with DNA is required for more precise and rational drug designing.
- Vibrational spectroscopic techniques (Infrared and Raman) can be used to establish correlations between spectral modifications and drug binding mode, sequence specificity, DNA melting and conformational changes, as well as structural variations of drug-DNA complexes in aqueous solution.