ABSTRACT
A fast electrostatic diagnostic and analysis scheme on nanosecond pulsed beams in the keV energy range has been developed in the Malmberg-Penning trap ELTRAP. Low-noise electronics has been used for the detection of small induced current signals on the trap electrodes. A discrete wavelet-based procedure has been implemented for data postprocessing. The development of an effective electrostatic diagnostics together with proper data analysis techniques is of general interest in view of deducing the beam properties through comparison of the postprocessed data with the theoretically computed signal shape, which contains beam radius, length, and average density as fit parameters.
ABSTRACT
We investigate the intensity noise induced by pump-power fluctuations in a diode-pumped single-frequency codoped Tm-Ho:YAG laser and we measure, in the frequency domain, the corresponding transfer function. Good agreement between the measured transfer functions and the theoretical prediction is found. A relative intensity-noise level of ~- 110 dB/Hz from ~1 kHz to the relaxation-oscillation frequency, with complete suppression of the relaxation-oscillation peak, is achieved by use of a suitable optoelectronic feedback circuit.
ABSTRACT
The amplitude noise responses of optical-frequency-discriminating systems, based on Fabry-Perot cavities with intensity noise compensation, are analyzed considering also the effect of the resonator transient. From the point of view of amplitude noise immunity, systems based on transmission or reflection alone behave in a quite similar way within the discriminator bandwidth, whereas a proper combination of both these signals not only increases the sensitivity to frequency noise but also allows for higher rejection to amplitude noise.
ABSTRACT
The FM spectroscopy technique has been applied to two frequency-doubled Nd:YAG lasers to achieve absolute frequency stabilization against the hyperfine structure components of the rovibronic P(54) 32-0 iodine line at 532 nm. A fractional frequency stability of 2 x 10(-13) tau(-1/2) has been obtained for integration times in the range of 1 ms < tau < 10 s. For longer integration times the stability level remains below 10(-13), reaching a minimum value of 4.6 x 10(-14) at 100 s. This high stability level is, to our knowledge, the best value achieved against iodine lines by this locking method and for a fully transportable system.
ABSTRACT
A comprehensive study of a diode-pumped Er:Yb:glass microchip laser, operating at 1530-nm wavelength, is presented. The operating conditions wherein a linearly polarized, single longitudinal and transverse mode operation is achieved are indicated. An optimum pump spot size that minimizes the threshold pump power and maximizes the slope efficiency is experimentally found and theoretically justified by a space-dependent rate-equation model.
