Abstract: An attenuator for high power laser beams, the attenuator has an annular b dump through which the beam passes diametrically and in which the beam passes successively through a pair of pivoting transmissive and reflective element. These elements are individually mounted on intermeshed gears so that the elements are adjustable through equal and opposite angles. At each element a portion of the beam is reflected toward the dump and a portion transmitted, the relative energy in each portion being determined by the angle of the elements to the beam so that adjustment of this angle determines the amount of attenuation. The beam is offset oppositely by refraction at each element so that the attenuator does not change the beam path. The elements are, preferably, elements commonly used as edge filters, that is, interference filters having an abrupt monotonic transition with wavelength from reflection to transmission.

Abstract: The total optical loss caused by laser induced damage to an optical component is measured by monitoring the phase shift during mirror reflectance or transmission. The phase shift is directly proportional to the amount of loss. A secondary laser illuminates the area under test with a coherent light beam well below the component's damage threshold. This reference beam is modulated. The reflected or transmitted reference beam is monitored by a photomultiplier tube whose output is fed to a lock-in circuit. The lock-in circuit compares the phase of the received light to the induced modulation.

Abstract: Optical devices which reduce the risk of damage by high energy laser pulses re made by applying particles to the surface of optical components. The particles serve as plasma initiation sites. The particles are made of material capable of producing large numbers of free electrons when illuminated above a preselected power level. Above the preselected power level, transmittance or reflectance of the optical component is limited by the plasma created by the free electrons.

Abstract: A binary solvent for liquid dye laser systems comprising a surfactant having a hydrophobic end and a hydrophilic end in a viscous polar solvent provides a method of improving the output, efficiency and lifetime of laser dyes, particularly in non-flowing liquid dye laser systems.

Abstract: An apparatus for observing defects in and evolution of induced damage on a est surface is created by combining an illumination system with a magnification system. A visible light source is used to illuminate the surface of an optical sample. A test laser system is aligned to illuminate the identical surface areas of the optical sample with light of preselected wavelength (frequency) and intensity. A telescope is focused on the illuminated surface area. The output image of the telescope is fed to a video camera system which in turn is connected to a video tape system.