摘要:

The lifetime &tgr; of the storage effect in mixtures of cholesteric and nematic liquid crystals is found to depend exponentially on theL/P(thickness/pitch) ratio. &tgr; can be changed from 1 min to several days by varyingL/Pfrom 2 to 15.

ISSN:0003-6951    

DOI:10.1063/1.1654216

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Cavity misalignment of a helical TEA CO2laser, due to thermal bending of the beam, as well as thermal focusing effects has been observed. The spectral distribution of the energy is found to be invariant with gas mixtures, and the optimum N2: CO2ratio for peak power output is shown to be 1 : 1, with the addition of He being of no apparent value.

ISSN:0003-6951    

DOI:10.1063/1.1654217

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Current‐controlled negative resistance is observed inn‐InSb in the impact‐ionization region under nearly parallel electric and magnetic fields at 77 K. Furthermore, coherent low‐frequency oscillations associated with negative resistance are observed by means of an external resonance circuit. Frequencies of coherent oscillations (5–22 MHz) depend strongly on the external circuit but are independent of the magnetic field intensity.

ISSN:0003-6951    

DOI:10.1063/1.1654218

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Exact coincidences between infrared vibration‐rotation transitions of NH3and CO2or N2O laser lines have been obtained using high‐field Stark effect. Different schemes of pumping have been used, giving either increase or decrease of microwave absorption.

ISSN:0003-6951    

DOI:10.1063/1.1654219

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A series of experiments were performed on aluminum targets in order to find simple methods of increasing the stress and impulse using a laser. It was found by coating the aluminum targets with thin layers of transparent relatively volatile materials that order‐of‐magnitude increases were obtained over irradiating bare targets. Stress‐wave amplitudes of 7.9 kbar were measured.

ISSN:0003-6951    

DOI:10.1063/1.1654220

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

P‐branch laser oscillations have been observed in thev= 1 →v= 0 band of HF gas, optically pumped byR‐branch lines of a pulsed HF laser. The observed gains are large (> 10% cm−1) and the conversion efficiencies are high. In a ring cavity the system shows directional gain anisotropy characteristic of unidirectional laser amplifiers proposed recently.

ISSN:0003-6951    

DOI:10.1063/1.1654221

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Active mode locking of a high‐pressure cw waveguide CO2laser is reported. Pulse widths as short as 3 nsec are obtained. The results are shown to be in good agreement with existing theory.

ISSN:0003-6951    

DOI:10.1063/1.1654222

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The use of a spectroscopic method for analysing an rf‐sputtering glow discharge is described. Both pure CaO disks and ones doped with Sm and Tm were used as targets, and the purpose of the sputtering was to prepare luminescence films. The sputtering was carried out in atmospheres of Ar, O2, N2, and Ne. The intensity of the strongest peak of calcium was measured in these discharges as a function of the distance from the target and of the rf voltage used. It was observed that impurities, in this case H and N2, were revealed, and a regular calcium flux from the target to the substrate could be well controlled by this method.

ISSN:0003-6951    

DOI:10.1063/1.1654223

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A stripe pattern observed in orthoferrites illuminated at oblique incidence, previously explained using a ``virtual grating'' effect is reinterpreted as an interference pattern of two waves created at the domain boundary. The theory is extended to include the decrease in stripe spacing as the wall orientation is changed.

ISSN:0003-6951    

DOI:10.1063/1.1654224

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A novel source of time‐varying losses in electron‐beam‐pumped GaAs lasers is described. Over the range of electron‐beam voltages typically employed in such lasers, this loss initially greatly exceeds that due to reflectivity losses at the cavity end faces. This loss is predicted to fall off rather dramatically as a function of time after the start of the pumping pulse. Such a dynamic loss has a number of consequences. In particular, it leads to a source of faster‐than‐band‐gap wavelength tuning of the laser emission through an effect somewhat akin to the inverse of a dynamic Burstein shift.

ISSN:0003-6951    

DOI:10.1063/1.1654225

出版商:AIP    

年代:1972

数据来源: AIP