Abstract A thin film of active laser material having a thickness of an integral number of one-half wavelengths of the laser emission energy is disposed between two multilayer films having high reflectance properties relative to the wavelength of energy emitted by the active laser material while offering relatively good transmittance to a source of energy directed to the active laser material to raise its energy level. The multilayer films are each comprised of a number of layers alternating in high and low index of refraction and having a thickness of the order of one-quarter wavelength of the emitted laser energy. The multilayer high reflectance films disposed on either side of the thin film of active laser material may be supported on an appropriate substrate and the assembly is positioned in the path of an input signal which it is desired to filter and amplify as well as in the path of a source of excitation energy to produce an output signal commensurate in frequency with a known or determinable component of the input signal and in amplified form.
A thin film active interference filter as claimed in claim 1 and including multiple thin films of laser material disposed between reflecting layers.
Claim 2
Dependent Claim
40 words
A thin film active interference filter as claimed in claim 1 wherein said layers are of alternate high and low indices of refraction and each having a thickness of substantially one-quarter wavelength of the wavelength it is desired to amplify.
Claim 3
Dependent Claim
20 words
A thin film active interference filter as claimed in claim 3 wherein sad multiple reflecting layers are of dielectric materials.
Claim 4
Dependent Claim
28 words
A thin film active interference filter as claimed in claim 3 wherein said layers of alternate high and low index of refraction material are ZnS and MgF, respectively.
Claim 5
Dependent Claim
49 words
A thin film active interference filter as claimed in claim 3 and including multiple thin films of laser material disposed between multiple reflecting layers having alternate high and low indices of refraction and each having a thickness of substantially one-quarter wavelength of the wavelength it is desired to amplify.