Translator Disclaimer
Paper
28 July 2014 Development of compact and ultra-high-resolution spectrograph with multi-GHz optical frequency comb
Author Affiliations +
Abstract
In recent years, a calibration method for an astronomical spectrograph using an optical frequency comb (OFC) with a repetition rate of more than ten GHz has been developed successfully [1-5]. But controlling filtering cavities that are used for thinning out longitudinal modes precludes long term stability. The super-mode noise coming from the fundamental repetition rate is an additional problem. We developed a laser-diode pumped Yb:Y2O3 ceramic oscillator, which enabled the generation of 4-GHz (maximum repetition rate of 6.7 GHz) pulse trains directly with a spectrum width of 7 nm (full-width half-maximum, FWHM), and controlled its optical frequency within a MHz level of accuracy using a beat note between the 4-GHz laser and a 246-MHz Yb-fiber OFC. The optical frequency of the Yb-fiber OFC was phase locked to a Rb clock frequency standard. Furthermore we also built a table-top multi-pass spectrograph with a maximum frequency resolution of 600 MHz and a bandwidth of 1 nm using a large-size high-efficiency transmission grating. The resolution could be changed by selecting the number of passes through the grating. This spectrograph could resolve each longitudinal mode of our 4-GHz OFC clearly, and more than 10% throughput was obtained when the resolution was set to 600 MHz. We believe that small and middle scale astronomical observatories could easily implement such an OFC-calibrated spectrograph.
© (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mamoru Endo, Takashi Sukegawa, Alissa Silva, and Yohei Kobayashi "Development of compact and ultra-high-resolution spectrograph with multi-GHz optical frequency comb", Proc. SPIE 9147, Ground-based and Airborne Instrumentation for Astronomy V, 91477Y (28 July 2014); https://doi.org/10.1117/12.2055788
PROCEEDINGS
6 PAGES


SHARE
Advertisement
Advertisement
RELATED CONTENT

First light of a laser frequency comb at SALT
Proceedings of SPIE (August 09 2016)
Cavity designs for GHz frequency combs
Proceedings of SPIE (February 20 2017)
The spectrum of Th Ar hollow cathode lamps in the...
Proceedings of SPIE (June 30 2006)

Back to Top