Bio-stimulation by a light is called the Light Therapy (LT) and an Infrared Illuminator (IRI) provides the human sleeping in a Healing Bed (HB) continuously a dose of the IR radiation. General
specifications for the IRI given below and its data are discussed in the paper.
(1) Use of 60" wide by 80" long queen size bed.
(2) A LED providing 1.5 mw at 1550 nm is selected.
(3) 60 LED are mounted in series and parallel on a chip and this chip is mounted on top of the HB.
We evaluate the performance potential of a diode pumped Nd: YAG rod laser by finding the absorbed pump distribution using ASAP, pump induced thermal lensing, gain medium surface distortion and stresses using FEMLAB and depolarization losses using MATLAB. Beam propagation in the optically distorted Nd:YAG rod and the free space part of the cavity, and the output laser beam were determined with a computational scheme we developed which employs the beam propagation method combined with sparse matrix technology. We propose a special cavity design that can select the spatial eigen mode shape of the laser and simultaneously compensate for pump induced thermal lensing, gain medium surface distortion and birefringence. The converged solutions calculated this special cavity design give both high extraction efficiency and good output beam quality. Sensitivity of the output beam to mirror tilt, thermal induced mirror distortion, and errors in the cavity length or the optical distortions in the rod were also calculated.
Data on laser-induced damage threshold (LIDT) in optical materials show the damage energy fluence dependence on the laser wavelength. Also, these LIDT measurements depend on the type of materials and its physical properties. The fundamental mechanism of materials damage can be due to ablation, melting, vaporization and/or thermal stresses. In general, optical materials require a very high-energy fluence for its damage. Therefore, the LIDT in optical materials can be considered as a limiting case for the materials damage due to the propagation of the ELectro- magnetic radiation. In this paper, equations for materials damage by a laser radiation are derived based on the melting and vaporization processes. The measured and calculated data are found to agree well.
An eye safe Ho:YAG laser operating cw at 2.09 micrometers was used as the transmitter for this laser radar (ladar) system. The diode pumped Ho:YAG laser provided up to 100 mW of single frequency output power. An InGaAs detector was selected as the off-set homodyne receiver for vibration signatures. This paper describes the design and characteristics of the laser vibration sensor that is based on laser Doppler radar. Initially, the sensor was calibrated using a piezoelectric loudspeaker, then vibrational signatures were obtained for automobiles having four and eight cylinder engines. This two micron laser Doppler radar permitted high- resolution vibrational signatures detection, remotely, at ranges up to 50 meters.
We have demonstrated a silver gallium selenide (AgGaSe2) based optical parametric oscillator (OPO) tunable from 2.75 micrometers to longer than 6 micrometers (limited by the measuring spectrometer) with greater than 1 mJ per pulse output energy in this range. The crystal used was 8 X 8 X 27 mm. We used a 60 mJ, near Gaussian, 2.09 micrometers chromium, thulium, holmium doped YAG (CTH:YAG) laser pump source, Q-switched by an AO modulator to produce approximately 50 ns pulses. As with most OPO's the output energy is limited by damage to the nonlinear crystal. We measured the damage threshold of both coated and uncoated surfaces to be approximately 0.9 J/cm2 and 1.2 J/cm2 respectively.
Materials used for electro-optics (EO) and acousto-optics (AO) Q-switches in lasers include fused silica (SiO2), lithium niobate (LiNbO3), and tellurium oxide (TeO2). The damage threshold measured for these materials is presented in this technical paper. Also, the Q-switch data collected for chromium, thulium, and holmium doped YAG (CTH:YAG) laser operating at 2.1 micrometers are reported.
Silver gallium selenide (AgGaSei) crystal for efficient second-harmonic-generation of C02 laser lines has been demonstrated using a pulsed laser. However, the use of this crystal in continuous wave (CW) lasers is limited due to its low laser damage threshold. In this paper, laser damage threshold measurements obtained using a 9 µm C02 laser will be discussed. The data obtained for the frequency doubling of 9 µm to 4.5 µm will be presented.
A miniature laser with a total volume less than 15 cu cm and weight less than 100 g has been designed, fabricated, and assembled. The laser uses a composite rod consisting of Nd:Cr:GSGG material rod cladded with an Er:Cr:YSGG tube. The laser provides output at 1 and 3 micron wavelengths. The size and weight reduction is obtained by chemical pumping which eliminates the prime power and the power supply. The laser is used as an illuminator in a direct detection radar.