Using an Optical Novelty Filter to Enhance Contrast in Photothermal Refraction Spectrometry
AIP Conference Proceedings: Photoacoustic and Photothermal Phenomena
F. Scudieri and M. Bertolotti
Apparatuses producing refractive index perturbation images using optical novelty filters are described. The simplest apparatus uses an optical novelty filter to convert infrared laser absorption into visual images. The optical novelty filter, formed in the conjugate plane beyond the sample, is an adaptable, matched spatial rejection filter. Rapid refractive index perturbations in the sample produce phase shifts in the probe laser beam resulting in real spatial components in the conjugate plane. The real, high spatial frequency components pass through the optical novelty filter, resulting in high contrast signals. Under ideal conditions, the interference pattern will result in an image of the phase shift resulting from the refractive index perturbation of the sample.
Using an Optical Novelty Filter to Enhance Contrast in Photothermal Refraction Spectrometry Stephen E. Bialkowski Photoacoustic and Photothermal Phenomena, F. Scudieri and M. Bertolotti, Ed., AIP Conference Proceedings 463 67‐71 1999