Y. Sutoh

Birefringence imaging of human skin by polarization-sensitive spectral interferometric optical coherence tomography

We have developed a spectral interferometric optical coherence tomography (OCT) system with polarization sensitivity that is able to measure a two-dimensional tomographic image by means of one-dimensional mechanical scanning. Our system, which has an axial resolution of 32 mum , calculates the distribution of each element of the Müller matrix of a measured object from 16 OCT images. The OCT system successfully reveals the birefringent nature of human skin tissue.

Optical coherence tomography by spectral interferometric joint transform correlator

A surface measurement system was constructed in which a spectral interferometer and a joint transform correlator are combined. The setup is able to determine the three-dimensional (3-D) profile of an object to a resolution of 70 μm. Measurement of the pathlength difference of two arms of the Michelson interferometer and several experimental results using 3-D samples are described.

Spectral interferometric optical coherence tomography with nonlinear β-barium borate time gating

A high-speed, all optical coherence tomography system was designed and constructed. This tomography system employs spectral interferometry and optical Fourier transformation to reduce the number of mechanical scanning dimensions required for multidimensional profilometry. The system also employs a time gate comprising a beta -barium borate crystal driven by a femtosecond laser pulse to improve measurement time. This system has 43-mum depth resolution and 150-fs temporal resolution and is capable of taking 1000 cross-sectional image frames per second.

Phase-resolved correlation and its application to analysis of low-coherence interferograms.

A new signal-processing technique is proposed that involves a phase-resolved correlation method that one can use to determine the phase distribution of low-coherence interferograms. This method improves the sensitivity and resolution of low-coherence interferometers. The depth structure of an aluminum oxide-coated aluminum mirror was determined by use of a low-coherence interferometer with this method. Three signal peaks were successfully extracted from a noisy interferogram.

Time-space conversion of femtosecond light pulse by spatio-temporal joint transform correlator

Abstract A new method to obtain the auto-correlation of an ultrafast light pulse spatially and parallel is proposed. The method is based on a conventional optical computing technique, joint transform correlator, and a spectral filtering method to control ultrafast light pulses temporally. A simple experimental determination of the pulse-separation of twin pulses, is demonstrated. In the experiment, the optically addressable spatial light modulator is used as a spectrum-power spectrum conversion device, and the temporal accuracy of the system is 12.4 fs.

Spectral interferometric tomography with optical nonlinearity

A three-dimensional profile measurement system employing a spectral interferometer and a nonlinear /spl beta/-barium borate (BBO) crystal is constructed. The measurement result of the surface structure of the stepped surface object is shown.

Analysis of spatiotemporal coupling in a femtosecond pulse shaper by the Wigner distribution function

Masahiko Mori National Institute of Advanced Industrial Science and Technology 1-1-4, Umezono, Tsukuba, Ibaraki, 305-8568 Japan Abstract. The spatiotemporal coupling effect in ultrafast light pulses is described by the Wigner distribution function. This approach enables us to calculate: the output electric field intensity profile by defocusing lenses, grating pairs with different grating constants, lenses with different focal lengths, and combinations of these in pulse shapers. We also gain a clear understanding of the spatiotemporal properties of pulse shaping.

Spatio-temporal joint pulse shaper: analysis of the property by Wigner distribution function

Spatio-temporal pulse shaper which controls the spatial and temporal profile of an ultrafast light pulse. The pulse shaper uses the spatio-temporal coupling effect in a pulse shaper. In this paper, the quantitative property is analyzed numerically by using Wigner distribution function. By the analysis, it is confirmed that spatio-temporal output pulse track forms the differentiation of the phase mask.