Although optical absorption is an intrinsic materials property, it can be manipulated through structural modification. Coherent perfect absorption increases absorption to 100% interferometrically but is typically realized only over narrow bandwidths using two laser beams with fixed phase relationship. We show that engineering a thin film's photonic environment severs the link between the effect...

This paper reports on the pressure dependence of the optical absorption edge of ZnO in the wurtzite and rock-salt phase, up to 14 GPa. Both vapor-phase monocrystals and pulsed-laser-deposition thin films have been investigated. In both types of samples the wurtzite to rocksalt transition is observed at 9.7G0.2 GPa. The absorption tail of the fundamental gap, as measured in monocrystals, exhibit...

Four kinds of single-wall carbon nanotubes (SWNTs) with different diameter distribution have been synthesized and optical absorption spectra have been measured. Three large absorption bands due to the optical transitions between spike-like density of states, characteristics of SWNTs, were observed from infrared to visible region. Comparing with the calculated energy band, it has been concluded ...

Synchrotron-radiation computed tomography has been applied in many research fields. Here, PITRE (Phase-sensitive X-ray Image processing and Tomography REconstruction) and PITRE_BM (PITRE Batch Manager) are presented. PITRE supports phase retrieval for propagation-based phase-contrast imaging/tomography (PPCI/PPCT), extracts apparent absorption, refractive and scattering information of diffracti...

We present a novel spectroscopic method based on a phase-modulated interferometer which is suitable for the high-precision measurement of absorption and index of refraction profiles. A comparison with competing methods, that is with interferometry and FM spectroscopy, is given. The combination of these two methods, the phase-modulated interferometer, is shown to be best suited for experiments a...

Optical data manipulation technologies increasingly employ densely aperiodic optical 3D phase elements. Refinement of such technologies will require the capability to quantitatively characterize the volumetric dielectric modulation of an optical sample to a high level of precision and spatial resolution. We present a scanning transmission microscopy system that uses a position-sensitive detecto...

A moiré pattern is created by superimposing two black-and-white or gray-scale patterns of regular geometry, such as two sets of evenly spaced lines. We observed an analogous effect between two transparent phase masks in a light beam which occurs at a distance. This phase moiré effect and the classic moiré effect are shown to be the two ends of a continuous spectrum. The phase moiré effect allow...

The kinetics of the 520 mmu absorption change in spinach chloroplasts and Chlorella vulgaris following a flash from the ruby laser have been determined as follows: rise halftime </= 0.3 x 10(-6) second; rapid recovery halftime = 5 to 6 x 10(-6) second; intermediate recovery halftime = 4 x 10(-4) second (spinach chloroplasts only); slow recovery halftime = 12 to 170 x 10(-3) second, dependent on...