摘要:

End‐pumped lasing of thin CdS crystals is reported for electron energies down to 5 kV at 77°K and 9 kV at room temperature as a result of special treatment of the Fabry‐Perot mirrors. These mirrors consisted of 500 Å of aluminum on the bombarded side and a multi‐layer dichroic reflector on the opposite side. The very low voltage thresholds were obtained only where localized electron beam heating was used to produce bubbles in the aluminum; in other areas where the aluminum was flat, the threshold was greater than 25 kV. Improved reflectivity and possibly a confocal cavity contribution are believed to be responsible for this pronounced decrease of threshold.

ISSN:0003-6951    

DOI:10.1063/1.1653082

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Laser action at 10. 6 &mgr;m has been achieved in CO2&sngbnd;N2&sngbnd;He gas mixtures at all pressures up to atmospheric by means of fast electrical discharges transverse to the laser axis. The atmospheric pressure of operation is very promising as the laser energy per pulse increases with pressure and the average power per unit volume is proportional to the square of the operating pressure. A brief description of a simple laser of this type, operating at atmospheric pressure is given along with some of the major achievements to date using this technique.

ISSN:0003-6951    

DOI:10.1063/1.1653083

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The steady‐state characteristics of avalanchingP+NN+junctions have been calculated numerically as a function of temperature when carrier trapping on a multiple level trap is present in the space‐charge region. Theory and experiment are compared for two devices of known doping profile. Negative temperature coefficients are predicted and measured at current densities higher than 50 A/cm2and are proposed as the catastrophic failure mechanism for avalanche devices in a neutron irradiation environment. The agreement between experiment and theory substantiates assumptions about the insensitivity of the results to the value of capture rates used in the calculations.

ISSN:0003-6951    

DOI:10.1063/1.1653084

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The upper level lifetime for the 4416‐Å transition in the helium‐cadmium laser has been measured to be 670 ± 70 nsec. The measurements were accomplished by rapidly removing the intracavity laser power while monitoring the sidelight emission from the discharge at the laser wavelength. This measurement technique is applicable to other laser systems with upper level lifetimes which are long compared with the cavity dumping time, and has the advantage of providing a direct measurement of the upper level lifetime.

ISSN:0003-6951    

DOI:10.1063/1.1653085

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

We have measured the width of the zero‐magnetic‐field power dip for the 4416‐Å transition of the He&sngbnd;Cd laser. The width is proportional to the decay rate of the electric quadrupole moment,&ggr;a(2), of the upper laser level.&ggr;a(2), which is of the order of 1 MHz, was found to vary linearly with He pressure. This variation is attributed toMJ‐mixing collisions with He atoms. The value of the ``alignment'' cross section&sgr;He(2)is estimated from the slope of this pressure dependence. The decay rate was also found to depend on the Cd density in the discharge. This dependence is tentatively attributed to deexcitation andMJ‐mixing collisions with electrons.

ISSN:0003-6951    

DOI:10.1063/1.1653086

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The (111)‐, (200)‐, and (220)‐lattice planes of small vapor‐deposited gold crystals with 2.35‐, 2.04‐, and 1.44‐Å respective interplanar lattice spacings were resolved by high‐resolution transmission electron microscopy. The simultaneous resolution in one micrograph of the three different lattice spacings and the elimination of azimuthal orientation preferences of the imaged lattice planes were achieved by using conical instead of axial specimen illumination methods.

ISSN:0003-6951    

DOI:10.1063/1.1653087

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A nonuniform photon flux distribution over the length of the active region in semiconductor injection lasers has been found by investigating the scattered light perpendicular to the direction of the stimulated light wave. This effect is present only in low‐Qlasers.

ISSN:0003-6951    

DOI:10.1063/1.1653088

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Spontaneous emission from the &ngr;3fundamental vibration in SF6gas after excitation by a pulse from aQ‐switched CO2laser is observed. The pressure dependence of the flourescence decay time indicates that, at low pressure, diffusion of excited molecules followed by deactivation at vessel walls is the dominant relaxation mechanism. At higher pressures, the time for collisional deactivation within the bulk of the gas is measured. Evidence which suggests that a longitudinal‐acoustic‐shock wave was present in the gas at higher pressures is given.

ISSN:0003-6951    

DOI:10.1063/1.1653089

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A new scheme for optically exciting intense microsound is proposed. The intense acoustic waves are generated by the enormous spatially periodic pressure gradients that arise under certain conditions from the interference of two high‐power optical beams of short time duration. The technique provides a tuneable source of bulk and surface micro‐acoustic waves.

ISSN:0003-6951    

DOI:10.1063/1.1653090

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

We report a new method of coupling a laser beam to thin‐film optical guided waves which utilizes an optical grating that is made from photoresist and fabricated directly on the film. High efficiency coupling (∼40 %) into a single mode in a glass film is observed.

ISSN:0003-6951    

DOI:10.1063/1.1653091

出版商:AIP    

年代:1970

数据来源: AIP