<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Tunable <span style="font-size:14.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:HiddenHorzOCR;color:black; mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">mid-infrared spectrometer <span style="font-size:14.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">based on KTA crystal to study fundamental V₃ band of methane</span></span></span>

Abstract

Tunable mid-infrared radiation in the range 3-3.5μm have been generated by difference frequency mixing in a biaxial potassium titanyl arsenate (KTA) crystal. The fundamental input radiations are the second harmonic of a commercially available Nd:YAG laser radiation (i.e. 532 nm) and the same pumped visible dye laser radiation. Using the generated tunable radiation the room temperature absorption spectra of R-branch of the <i>v</i>₃ band of methane at 120 mbar pressure have been studied. Pressure dependent absorption of P(7) line of the <i>v</i>₃ band of methane have also been studied. The absorption

<span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">measurements have been performed in an indigenously built single pass gas celi of length <span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:hiddenhorzocr;color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">33cm.</span></span>