HIGH RESOLUTION SPECTROSCOPY OF NAPHTHALENE CALIBRATED BY AN OPTICAL FREQUENCY COMB

Nishiyama, Akiko

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https://hdl.handle.net/2142/79295 Copy

Description

Title

HIGH RESOLUTION SPECTROSCOPY OF NAPHTHALENE CALIBRATED BY AN OPTICAL FREQUENCY COMB

Author(s)

Nishiyama, Akiko

Contributor(s)

• Misono, Masatoshi
• Matsuba, Ayumi
• Nakashima, Kazuki

Issue Date

23-Jun-15

Keyword(s)

Mini-symposium: High-Precision Spectroscopy

Abstract

In high-resolution molecular spectroscopy, the precise measure of the optical frequency is crucial to evaluate minute shifts and splittings of the energy levels. On the other hand, in such spectroscopy, thousands of spectral lines distributed over several wavenumbers have to be measured by a continuously scanning cw laser. Therefore, the continuously changing optical frequency of the scanning laser has to be determined with enough precision. To satisfy these contradictory requirements, we have been developed two types of high-resolution spectroscopic systems employing an optical frequency comb. One of the systems employs RF band-pass filters to generate equally spaced frequency markers for optical frequency calibration, and is appropriate for wide wavelength-range measurement with relatively high scanning rate.$^a$ In the other system, the beat frequency between the optical frequency comb and the scanning laser is controlled by an acousto-optic frequency shifter. This system is suitable for more precise measurement, and enables detailed analyses of frequency characteristics of scanning laser.$^b$ In the present study, we observe Doppler-free two-photon absorption spectra of $A^1B_{1u} (v_4 = 1) leftarrow X^1A_g (v = 0)$ transition of naphthalene around 298 nm. The spectral lines are rotationally resolved and the resolution is about 100 kHz. For $^qQ$ transition, the rotational lines are assigned, and molecular constants in the excited state are determined. In addition, we analyze the origin of the measured linewidth and Coriolis interactions between energy levels. To determine molecular constants more precisely, we proceed to measure and analyze spectra of other transitions, such as $^sS$ transitions. $^a$ A. Nishiyama, D. Ishikawa, and M. Misono, J. Opt. Soc. Am. B 30, 2107 (2013). $^b$ A. Nishiyama, A. Matsuba, and M. Misono, Opt. Lett. 39, 4923 (2014).

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

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http://hdl.handle.net/2142/79295

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