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

Advances in multispectral and hyperspectral imaging for archaeology and art conservation

Multispectral imaging has been applied to the field of art conservation and art history since the early 1990s. It is attractive as a noninvasive imaging technique because it is fast and hence capable of imaging large areas of an object giving both spatial and spectral information. This paper gives an overview of the different instrumental designs, image processing techniques and various applications of multispectral and hyperspectral imaging to art conservation, art history and archaeology. Recent advances in the development of remote and versatile multispectral and hyperspectral imaging as well as techniques in pigment identification will be presented. Future prospects including combination of spectral imaging with other noninvasive imaging and analytical techniques will be discussed

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