The injection-locking of laser diodes with adjustable frequency difference of the order of 1 GHz with respect to the frequency of a master lber is demonstrated. Each slave laser frequency can be individually switched between up to five discrete values simply by changing its operation current. The presented scheme does not need any RF sew0 loop or optical filters in the locking path of the slave diodes.

Experimental data obtained from testing the DataPlay 32 mm disc and drive are presented. Of particular interest, due to the unique rotary tilt arm actuator and front surface head/media architecture is the data concerning shock, vibration, and temperature and humidity stress environments. Results demonstrate that the DataPlay optical drive and media are sufficiently robust for use in portable consumer electronics devices.

Based on new market opportunities for consumer electronics devices DataPlay has designed a new version small formfactor optical disc and drive featuring a capacity of 750MB per disc as compared to 500MB per disc of the original product. The NA of the optical pickup has been increased from 0.60 to 0.72. The track pitch of the media has been reduced from 0.74µm to 0.60µm, and the smallest mark size has been decreased from 435nm to 358nm. Details of the new design are presented as well as test results that show the higher capacity design is sufficiently robust to be used in consumer devices.

Data from future high precision cosmic microwave background measurements will be sensitive to the primordial helium abundance Y p . At the same time, this parameter can be predicted from big bang nucleosynthesis (BBN) as a function of the baryon and radiation densities, as well as a neutrino chemical potential. We suggest using this information to impose a self-consistent BBN prior on Y p and determining its impact on parameter inference from simulated planck data. We find that this approach can significantly improve bounds on cosmological parameters compared to an analysis which treats Y p as a free parameter, if the neutrino chemical potential is taken to vanish. We demonstrate that fixing the helium fraction at an arbitrary value can seriously bias parameter estimates. Under the assumption of degenerate BBN (i.e., letting the neutrino chemical potential ξ vary), the BBN prior's constraining power is somewhat weakened, but nevertheless allows us to constrain ξ with an accuracy that rivals that for bounds inferred from present data on light element abundances.

A review of small form factor optical storage (media diameters less than 50 mm) is presented with emphasis on the development of near-field technology. The current efforts are summarized together with the commercially desired attributes. The results of the examination of gallium phosphide (GaP) and diamond solid immersion lenses in conjunction with evanescent coupling are presented. A polarization-based gap error signal (GES) technique for air-gap servocontrol is described. Results indicate that the method is relatively insensitive to contamination on the surface and can resolve 100-nm surface features. A 50-GB 120-mm read-only memory (ROM) disc was successfully read and the results indicate that a 10-GB 32-mm diameter RW/ROM optical disc based on 650-nm lasers should be feasible.