We have developed and tested an antireflection (AR) coating method for silicon lenses used at cryogenic temperatures and millimeter wavelengths. Our particular application is a measurement of the cosmic microwave background. The coating consists of machined pieces of Cirlex glued to the silicon. The measured reflection from an AR-coated flat piece is less than 1.5% at the design wavelength. The...

We have developed and tested an antireflection (AR) coating method for silicon lenses at cryogenic temperatures and millimeter wavelengths. Our particular application is a measurement of the cosmic microwave background. The coating consists of machined pieces of Cirlex glued to the silicon. The measured reflection from an AR coated flat piece is less than 1.5% at the design wavelength. The coat...

A broadband non-dispersive thin-film polarizer for ultrafast applications is presented. The polarizer has a controllable flat-phase and a high extinction ratio of 23:1 in the working bandwidth from 680 nm to 900 nm. This bandwidth allows supporting laser pulses down to 12 fs. The unavoidable mechanical stress of the interference coating is completely compensated by a specially designed antirefl...

Subwavelength nanostructures are considered as promising building blocks for antireflection and light trapping applications. In this study, we demonstrate excellent broadband antireflection effect from thin films of monolayer silica nanospheres with a diameter of 100 nm prepared by Langmuir-Blodgett method on glass substrates. With a single layer of compact silica nanosphere thin film coated on...

Examining spectral regions outside of the band where an antireflection coating is specified can aid in finding optimal design solutions. The reflectance versus wavenumber plots at low frequencies indicate the overall thickness of the design. These plots also point to whether the design will provide the minimum possible average reflectance in the specified band. It has been discovered that these...

The application of a few basic principles, some empirical data, and experience is applied to estimate the average residual reflection expected in an AR coating as a function of bandwidth, wavelength, overall thickness, substrate index, available coating materials, and number of layers. This can be a useful tool for not only the thin film designer but also the non-designer or system engineer to ...

Recent investigations have added to and refined the understanding of the behavior of broadband antireflection coating designs and provided further guidance for achieving more nearly optimal designs. The ability to optimize designs wherein the overall optical thickness of the design is constrained to a specific value has allowed this investigation. A broader bandwidth than previously reported ha...

We show that a single-layer antireflection coating on a THz source of high refractive index can substantially increase the transmission of emitted THz pulses. Calculations indicate that the optimum coating thickness depends on the exact shape of the generated THz waveform and whether the transmitted waveform is to be optimized for the highest peak (temporal) amplitude, peak spectral amplitude, ...

Terahertz time-domain spectroscopy (THz-TDS) is able to extract optical or dielectric properties of materials, whether in the solid, liquid, or gas phase, in the T-ray frequency region. Spectroscopy of a liquid or gas often requires a receptacle to confine the sample. In order to allow T-rays to probe the sample effectively, the receptacle must have T-ray transparent windows. However, even thou...