Yb-Doped: YCOB Laser (DIV)

A tunable, solid state laser device with both visible and infrared laser emission is developed with a trivalent ytterbium-doped yttrium calcium oxyborate crystal as the host crystal. The Yb:YCOB crystal generates an infrared fundamental light over a wide bandwidth, from approximately 980 nanometers (nm) to approximately 1100 nm. The bandwidth generated by the Yb:YCOB crystal is approximately 100 nm wide and supports the generation of pulsed infrared light or when self-frequency doubled provides a compact, efficient, source of tunable, visible, blue or green laser light in wavelengths of approximately 490 nm to approximately 550 nm

Self Frequency-doubled Nd-doped YCOB Laser

Neodymium-doped yttrium calcium oxyborate (Nd:YCOB) is the single active gain element for a solid-state laser device capable of achieving both lasing and self-frequency doubling optical effects. A pumping source for optically pumping Nd:YCOB can generate a laser light output of approximately 400 mW at approximately 1060 nm wavelength and a self-frequency doubled output of approximately 60 mW at approximately 530 nm wavelength. Thus, a laser device can be designed that is compact, less expensive and a high-powered source of visible, green laser light

Direct measurement of thermal lensing in Cr\u3csup\u3e3+\u3c/sup\u3e-doped colquiirities

A two-dimensional code that takes into account the quantum defect, upconversion, and thermal quenching of fluorescence has been developed. The code provides the spatial distribution of temperature, upper-state lifetimes, and heating sources within a laser rod under longitudinal pumping, for all the cloquiirite laser materials. The output of this code for a 4-mm-diameter, 1.5% Cr:LiSGAF rod is shown

Measurement of thermal lensing in Cr \u3csup\u3e3+\u3c/sup\u3e-doped colquiriites

The first direct measurements of thermally induced lensing in end-pumped Cr 3+-doped LiSAF, LiSGAF, LiSCAF, and LiCAF are reported. Using a sensitive measurement technique, focal lengths as long as 40 m were measured. A thermal model has been created to determine the temperature rise as a function of position inside the laser crystal. This new model calculates the temperature distribution by considering quantum defect, upconversion, and upper state lifetime quenching as heating sources. Thermal lensing in the colquiriites is significantly reduced because of compensation of the temperature-dependent refractive index by the induced photoelastic stress inside the colquiriite crystal

Ycob Lasers

We review new developments with a new laser host material, YCa4O(BO3)3 or YCOB. Lasers based on this host material will open new opportunities for the development of compact, high-power, frequency-agile visible and near IR laser sources, as well as ultrashort-pulse sources. Efficient diode-pumped laser action with both Nd-doped and Yb-doped YCOB has already been demonstrated. Moreover, since these materials are biaxial and have high nonlinear optical coefficients, they have become the first laser materials available as efficient self-frequency-doubled lasers capable of providing tunable laser emission in several regions of the visible spectrum. Self-frequency doubling eliminates the need for inclusion of a nonlinear optical element within or external to the laser resonator. These laser materials possess excellent thermal and optical properties, have high laser-damage thresholds, and can be grown to large sizes. In addition they are non-hygroscopic. They, therefore, possess all the characteristics necessary for laser materials required in rugged, compact systems. Here, we summarize the rapid progress made in the development of this new class of lasers and review their potential for a number of applications

Optically Written Display

Two, three dimensional color displays having uniform dispersion of red, green and blue visible light emitting micron particles. Pumping at approximately 976 nm can generate green and red colors having an approximately 4% limit efficiency. One source can generate three colors with approximately limit efficiency. Modulators, scanners and lens can move and focus laser beams to different pixels forming two dimensional color images. Displays can be formed from near infrared source beams that are simultaneously split and modulated with micro electro mechanical systems, spatial light modulators, liquid crystal displays, digital micromirrors, digital light projectors, grating light valves, liquid crystal silicon devices, polysilicon LCDs, electron beam written SLMs, and electrically switchable bragg gratings. Pixels containing: Yb,Tm:YLF can emit blue light, Yb,Er(NYF) can emit green light, and Yb,Er:KYF and Yb,Ef:YF.sub.3 can emit red light

Second-harmonic generation in doped YCOB

Recently, second-harmonic generation (SHG) has been measured in two oxoborate crystals of YCOB and GdCOB. This study extends the development of the oxoborate crystal for nonlinear frequency conversion by investigating the effects of dopant ions on the crystalline structure and, as a consequence, improving the optical nonlinearity. Nonlinear harmonic generation has been measured in a wide range of oxoborate crystals that include YCOB [YCa4(BO3)3O], Nd:YCOB, and Yb:YCOB. Conversion efficiencies approaching 40% were measured with 20% Yb-doped YCOB for a pump power of approx. 11 MW

Second harmonic generation in Yb doped YCa4O(BO3)3

We report efficient second harmonic conversion in a new nonlinear optical crystal, Yb3+ doped YCa4O(BO3)3, that is non-hygroscopic, has good optical and mechanical properties, and can be grown in large sizes. The effect of Yb concentration on the harmonic conversion efficiency is also investigated. © 1998 Elsevier Science B.V. All rights reserved