Title :
Optical frequency standard at 532 nm
Author :
Eickhoff, Mark L. ; Hall, J.L.
Author_Institution :
Joint Inst. for Lab. Astrophys., Nat. Inst. of Stand. & Technol., Boulder, CO, USA
fDate :
4/1/1995 12:00:00 AM
Abstract :
We have constructed a frequency-doubled Nd:YAG laser source stabilized via modulation transfer spectroscopy to hyperfine absorption peaks in molecular iodine. The system is suitable for use as an optical frequency standard because of the excellent stability (σ<1×10-13 for τ⩾1 s) and reproducibility (75 Hz per ir laser) observed between two independent dissimilar systems. With heterodyne techniques, we have measured the hyperfine splittings of seven rovibrational transitions in 127I2. A computer fits the data for the hyperfine coupling constants based on a four term Hamiltonian. The residuals from these fits have a standard deviation as low as 520 Hz, displaying the best reported agreement to date with the quadrupolar hyperfine Hamiltonian. Modulation transfer lineshapes have been accurately recorded using rf offset phase-locking techniques with our two systems. Pressure shift (-1.3 kHz/Pa) and broadening (74 kHz/Pa) of the a1 component of R(56)32-0 have been derived from these lineshape measurements
Keywords :
frequency measurement; hyperfine structure; iodine; measurement standards; modulation spectroscopy; rotational-vibrational states; spectral line broadening; spectroscopy; 532 nm; 127I2; I2; Nd:YAG laser source; YAG:Nd; YAl5O12:Nd; broadening; four term Hamiltonian; frequency-doubled Nd:YAG laser source; heterodyne techniques; hyperfine absorption peaks; hyperfine coupling constants; hyperfine splittings; lineshape measurements; modulation transfer lineshapes; modulation transfer spectroscopy; molecular iodine; optical frequency standard; pressure shift; quadrupolar hyperfine Hamiltonian; reproducibility; residuals; rf offset phase-locking techniques; rovibrational transitions; stability; Electromagnetic wave absorption; Frequency; Laser stability; Laser transitions; Optical mixing; Optical modulation; Phase modulation; Pressure measurement; Reproducibility of results; Spectroscopy;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on