Suganda Jutamulia

Use of laser diode in joint transform correlator

The use of a laser diode in a joint transform correlator (JTC) is proposed. Effects of temporal coherence, spatial coherence, astigmatism, and elliptical beams are analyzed. Laser diodes can be used in JTC, and also can be used for the correlation process in a Vander Lugt correlator and reading a hologram. Even a light-emitting diode (LED) may be used for the purposes mentioned, if its exit facet is sufficiently small. Two methods for correcting a laser diode beam using a cylindrical lens or a pair of cylindrical lenses are also reviewed. A corrected laser diode can be used in JTC to totally eliminate the effect of astigmatism.

SPR prism sensor using laser line generator

A Kretschmann prism configuration uses a laser line generator, which includes a laser diode and a pair of cylindrical lenses having different optical powers in x and y directions. A metal layer is directly coated on one side of the prism. The line generator determines the length of the laser line and the divergent angle of the fan-shape light sheet. The length of the laser line on the metal layer is determined by the separation of the focus position of the laser light from the metal layer.

Beam correction optics for laser diodes

The beam emitted by a laser diode chip is elliptical and astigmatic. Various methods have been proposed and applied to remove the astigmatism and to produce a circular Gaussian beam. In this paper we will further propose the use of the laser diode beam correction optics in an external cavity laser. The light produced by the external cavity laser is not only circular, Gaussian, and non-astigmatic, but its coherence length is also significantly enhanced.

Guest Editorial: Special Section on Applications of Neural Networks in Optics

This PDF file contains the editorial “Guest Editorial: Special Section on Applications of Neural Networks in Optics” for OE Vol. 35 Issue 07

Pre-cataract surgery test using speckle pattern

A laser diode device for pre cataract surgery test is proposed. The operation is based on the speckle generated on the retina by the cataract lens, when the cataract lens is illuminated with a coherent laser light.

Compact one-lens fluorescence microscope using CMOS image sensor

A fluorescence imaging module includes a fluorescence sample, a lens, an emission filter, an image sensor, and an illuminating device disposed between the sample and the lens. The illuminating device comprises a truncated pyramid for bending light emitted by the excitation light source toward the central area of the fluorescence sample. Light from the excitation light source enters from a slanted side surface of the truncated pyramid and emerges at the top of the truncated pyramid to illuminate the sample. The fluorescence image of the sample is formed by the lens through the emission filter on the image sensor.

Lasers in light skin interaction

Lasers used in dermatological treatments are presented. Commercially available semiconductor lasers (laser diodes) are also presented for comparison. Potential applications of semiconductor lasers to noninvasive information processing or diagnosis as well as medical treatment are discussed. In addition, the current application of LEDs to dermatology is also included in the paper.

1D Fourier transform in optical information processing

We review applications of 1D Fourier transform to Fourier transform spectroscopy, optical coherence tomography, and fiber distributed sensor.

Differential Haar-Gaussian wavelet transform and its application to edge detection with large depth of focus

We propose a new wavelet transform, which is the differential Haar-Gaussian wavelet transform. This new wavelet transform is applied to the edge detection, which can be processed in both spatial and the frequency domains. The bandwidth-matching algorithm and the telecentric optics are used to achieve fast calculation, and to produce high-precision edge detection results with large depth of focus.

Application of laser diode to optical signal processing

The use of laser diode in joint transform correlator (JTC) is discussed as an example of potential applications to optical signal processing. Effects of the coherence and astigmatism of laser diode beam are analyzed. Two methods for correcting laser diode beam using a cylindrical lens or a pair of cylindrical lenses are also reviewed. A corrected laser diode can be used in JTC to totally eliminate the effect of astigmatism.