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High Precision Optical Frequency Synthesis

Posted on:2018-07-18Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y YaoFull Text:PDF
GTID:1318330512994256Subject:Optics
Abstract/Summary:PDF Full Text Request
The frequency instability and uncertainty of the state-of-the-art optical atomic clocks have been improved to the 10-18 level.They have been the most accurate and stable time/frequency references in the world,which enables us to explore a number of important applications using optical atomic clocks,such as test of the variation of fundamental constants,deep space navigation,geodesy.One of the key requirements in these applications is to coherently transfer the signals of optical clocks at specific frequencies to other frequencies in the optical region or even in the microwave region without degrading the frequency accuracy and the frequency stability of the signals from optical clocks.Therefore,the research of high precision optical frequency synthesis is significant.Since optical frequencies are on the order of 1014 Hz,far beyond the response bandwidth of most electronic components,microwave synthesis based on electronic technology is hardly to be applied in optical frequency synthesis.An optical frequency comb can output many equally spaced frequency components over an octave spectrum,allowing a direct link from radio frequency standard to optical frequencies and one optical frequency to another.In this thesis,the optical frequency division technique with high accuracy and low noise is studied with the narrow linewidth comb and the transfer oscillator scheme.An optical frequency reference microwave frequency reference technique for eliminating microwave noise is proposed,and a pre-settable optical frequency divider is realized for the first time.By comparing the frequency ratio between the fundamental and the second harmonic of a 1064 nm laser,the fractional frequency instability and uncertainty of the optical frequency divider in optical frequency division are demonstrated to be 6×10-19 at 1 s averaging time and 1.4×10-21,respectively.Based on the high precision optical frequency divider,an optical frequency synthesizer is constructed by accurately dividing the frequency of a 0.7 Hz-linewidth 1064nm laser to a widely tunable Ti:sapphire single frequency cw laser.The optical frequency synthesizer is able to output a narrow-linewidth,single frequency signal with high frequency stability at any desired frequency within 700-990 nm.By beating against an independent 778.6 nm ultrastable laser,the output of the OFS is tested to have an average linewidth of 1 Hz and frequency instability of 1.5×10-15 at 1 s,limited by the reference laser of the optical frequency synthesizer.Based on one single optical frequency comb,multiple channels of optical frequency synthesizer have been realized.The relative frequency instability and agreement between different channels are 8×10-19 and 2×10-21,respectively.The research of high-precision optical frequency synthesis technology can provide the necessary tools for the application of optical clock.At the same time,it provides an effective technical means for the development of precision spectroscopy and precision measurement.
Keywords/Search Tags:Optical frequency synthesis, optical frequency comb, optical atomic clock, narrow-linewidth ultrastable laser
PDF Full Text Request
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