This paper presents a new graphical method for selecting an optimum pair of optical glass and housing materials to simultaneously achromatize and athermalize a multilens system, by use of iterative method. To take into account the lens spacing and housing, we newly quantify the lens powers of the elements by weighting the ratio of the paraxial ray height at each element to them. In addition, we introduce the equivalent single lens and the expanded athermal glass map including a housing material. Even though there is no glass satisfying athermal and achromatic conditions, we can iteratively identify a pair of glass and housing materials by changing the power of equivalent lens.
All-solid-state intracavity Raman laser using a ceramic Nd:YAG laser and a KGd(WO4)2 nonlinear crystal has been
fabricated and its output characteristics has been investigated for the purpose of medical application. Yellow laser light at
the wavelength of 579 nm could be obtained by second harmonic generation of LBO crystal from the first Stokes
wavelength of 1159 nm which was converted by stimulated Raman scattering with the fundamental wavelength of
Nd:YAG laser. In the case of using output coupler of reflectivity of 95%, the maximum peak power was 230 W/pulse
with the pulse width of 9.3 ns under the condition of Q-switched mode operation. The maximum average power of about
30 mW was achieved at the pump power of 20 W.
A passively Q-switched diode-laser pumped ceramic Nd:YAG laser has been constructed and the output characteristics
has been investigated. The output efficiency of 36.1 % has been obtained with 1.1 at.% of neodymium concentration in
the ceramic YAG. For the case of neodymium concentration of 2.0 at.%, the output power decreases as the pump power
increases over 6 W. The output power has rapidly decreased more than 10 W of pumping, and the laser output has finally
disappeared at pumping power of 13 W. This phenomenon can be explained by the thermal lens effect in the laser
material. Passive Q-switching has been carried out using a Cr:YAG crystal in the resonator. The pulse width is 61.2 ns
and the repetition rate is 10.1 kHz at the pump power of 1 W. The beam propagation factor M2 has been measured to be
1.2, which shows good beam quality of the Q-switched pulse.
In fabricating optical thin films by evaporating dielectrics onto a glass substrate there are various unwanted errors for the structure of dielectric multilayers, for example, thickness errors, lack of thickness uniformity, anisotropic refractive indices of growing dielectric films in a certain direction, etc. In particular, it is of interest to take thermal diffusion into account in the process of alternate deposition of one low-index material and one high-index material. It is not possible to avoid the diffusion of thin films in vacuum deposition technology as long as the dielectric components of different refractive indices are to be thermally heated. It is the aim of this presentation to numerically determine the influence on the performance of the thin films from the thermal diffusion during the vacuum deposition inside a chamber system. It is required to solve the accurate equation[1,2] [see Eq.(2) below] for the reflection coefficients to find the performance of the thin films. In this presentation we confine ourselves to the thermal diffusion effects on the quarter-wave stacks of alternating two (high- and low-index) dielectric materials for high reflectance in a broad region and the filters which transmit only selected regions of spectrum. Here the dispersion has not been included in the calculations for simplicity.
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