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Design, Implemention And Application Of Frequency Stabilized Svstem Of The Narrow-linewidth Dye Laser

Posted on:2014-02-20Degree:DoctorType:Dissertation
Country:ChinaCandidate:F LiuFull Text:PDF
GTID:1228330398996897Subject:Atomic and molecular physics
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Owing to their broad wavelength tuning range, continuous-wave dye laser have been widely used in the laser spectroscopy and optical frequency standards, such as the measurement of hyperfine transitions of molecular iodine and Yb optical lattice clocks. However, the large frequency noises of free-running dye lasers result in broadened linewidth and large frequency excursion, severely affecting their effectiveness in above-mentioned applications. To realize a tunable laser source with ultra-stable frequency and narrow linewidth, we performed systematic investigations on the frequency stabilization of a continuous-wave dye laser. This thesis details and summarizes the design, implementation, and application of the frequency-stabilized dye laser system.To investigate design of servo loops and noise analysis, long-term and wideband laser intensity stabilization with an electro-optic amplitude modulator was carried out. An active control scheme using a single crystal to realize the long-term power stabilization was applied and a power instability of8×10-4was achieved (3-h measurement). Mechanical resonances in two crystals (LiNbO3and KTiOPO4) were mapped out and their influences on the control bandwidth were quantitatively investigated. A fast loop was designed to suppress the noise in high frequency and a2.5MHz bandwidth was achieved. Residual noises of two intensity-stabilized lasers (a Helium-Neon laser and a dye laser) were analyzed in detail.The frequency stabilization of continuous-wave tunable dye laser was realized in the thesis. Considering frequency characteristics of the dye laser, we developed a two-stage PDH frequency locked system to suppress large frequency noise in the dye laser. In the first stage, to cope with relatively large high-frequency components in the dye laser frequency noise, a compact intracavity electro-optic modulator that serves as a fast frequency actuator was designed and assembled. By using the intracavity electro-optic modulator and piezoelectric transducers installed on the cavity mirrors, the linewidth of dye laser was suppressed from2.2MHz to10kHz. In the second stage, acousto-optic modulators were served as frequency actuators. To avoid the location shift of diffraction beam and increase frequency dynamic range, double-pass diffraction of AOM was employed. To judge the linewidth of stabilized dye laser, we established two independent2-nd stabilization systems, and a44Hz linewidth was measured by the beating method.We applied the spectral narrow dye laser to the measurement of hyperfine transitions of molecular iodine. The spectral detecton devices of iodine molecule in free space and trapped in AEL crystal were built. Utilized balanced detection and lock-in amplified technology, with1μW of incident laser the detection sensitivity achieved to1‰. Using saturation spectroscopy technology, the high precision spectroscopy of iodine molecule in free space was measured by scanning the narrow dye laser frequency. In the experiment of low spectral resolution (0.1nm) with white light source and high spectral resolution (-MHz, or10-6nm) with dye laser, the iodine molecule confined in AEL crystal has polarized absorption and continuous spectroscopy in the scanning wavelength range.At the end of the thesis, we discussed the methods to improve the performance of spectrally narrow dye laser, and laid the foundation on the application in the high-resolution laser spectroscopy and optical frequency standards.
Keywords/Search Tags:laser frequency stabilization, dye laser, laser power stabilization, electro-optic modulation, laser spectroscopy
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