Improved 2nd harmonic rise-time in a thermal-lens-dominated extended-cavity micro-laser
Many commercially available compact, micro-cavity diode-pumped solid-state lasers achieve a stable resonator condition following the formation of an intra-cavity thermal lens. Typically, this thermal lens forms as a result of localized thermal expansion in the host material due to the very high optical power of the infrared pump beam. Additionally, most common DPSS host media, such as Nd:YAG and Nd:YVO4 exhibit high dn/dT, change in refractive index with temperature. Thermal lens formation time dominates stable resonator establishment and, thus, the rise-time of the intra-cavity-generated visible second-harmonic output light. Thermal lens formation time may range from 10's of microseconds to several milliseconds, depending on pump power, the host material dn/dT, and the volume and length of the host material. This paper describes a unique approach that improves the second-harmonic rise-time - and, thus, the modulation bandwidth - for high-power VECSELs by several orders of magnitude. This approach, while typically used in some laser systems for other purposes, allows direct modulation of high-power VECSELs to greater than 100 megahertz with second-harmonic rise-time of a few nanoseconds.
Diode Lasers for Displays
Efficient, frequency doubled surface emitting GaInAs based diode lasers and laser arrays operating in the red, blue and green have been developed and used for large and small format projection displays
Phytochemical and FT-IR Spectral Analysis of Certain Bamboo Species of SouthIndia
Bamboo with its varied uses has historically been an integral part of livelihoods and lifestyles in India. The present study was carried out to characterize the bioactive constituents present in the leaf extracts of certain bamboo species using Fourier transform infrared spectroscopic analysis (FT-IR). The various solvent extracts of various bamboo leaves subjected to qualitative analysis showed the availability of phytoconstituents including alkaloids, phenolic compounds, flavonoids, saponins, glycosides, terpenoids, steroids, coumarins and phytosterols. Quinones were completely absent in all the five bamboo species. The FT-IR spectrum confirmed the presence of sulphides (SS), phenols (C-O), aromatic compounds, thiols (S-H), aliphatic compounds (C-Cl) and amines (NH) in different bamboo species. The present investigation has also opened avenues for further research into the development of potent phytomedicines from different bamboo species.