ABSTRACT
We present detailed stability measurements on six He-Ne lasers which have been stabilized by matching the intensity of the two orthogonal polarization modes. The frequencies of five different lasers were closely monitored for 1 month. Another laser was studied for 2 yr. All the lasers exhibited a stability of 1 part in 10(10) over the periods of about an hour and better than 1 part in 10(8) over 1 yr. An absolute accuracy of ~1 part in 10(9) can be attained by interpolating the linear drift between calibrations performed 6 months to 1 yr apart. These 1-mW lasers are rugged and simple to operate.
ABSTRACT
Resolution sufficient to resolve second-order Doppler broadening (3.9 kHz) has been obtained for the Ca (1)S(0)-(3)P(1) transition (657 nm) by using an atomic beam and optical Ramsey fringe techniques. Laser-beam separations up to 21 cm yield Ca linewidths (HWHM) as narrow as 1 kHz. As resolution is increased to approach, then exceed the second-order linewidth, large asymmetries, shifts, and shape changes occur in the Ramsey fringe profile.
