Cihan Koc

Single resonance monolithic Fabry–Perot filters formed by volume Bragg gratings and multilayer dielectric mirrors

A new class of Fabry-Perot filters produced by a multilayer dielectric mirror deposited on top of a reflecting volume Bragg grating is described. The first fabricated prototype for the 852 nm region demonstrates a 30 pm bandwidth, 90+% transmission at resonance, and a good agreement with theoretical simulation.

Use of a broadband monitoring system for the determination of the optical constants of a dielectric bilayer

This paper extends a method previously applied to the determination of the optical constants of a high-index thin film to a dielectric bilayer. This method is based on the time recording of the spectral transmittance of the stack during its deposition with the help of an in situ broadband monitoring system.

Laser damage of silica and hafnia thin films made with different deposition technologies

A comparative study is made on the laser damage resistance of monolayers coatings made with different technologies. HfO2 and SiO2 thin films have been deposited on fused silica substrates with Dual Ion Beam Sputtering, Electron Beam Deposition (with and without Ion Assistance) and Reactive Low Voltage Ion Plating technologies. The laser damage thresholds of these coatings have been determined at 1064nm and 355nm using a nanosecond pulsed YAG laser, and a 1-on-1 test procedure.

Determination of the optical constants of a dielectric layer by processing in situ spectral transmittance measurements along the time dimension

This paper describes a new method, based on the use of a broadband monitoring system, that allows to determine the spectral dependence of the optical constants of a tantala layer without the use of a dispersion model.

Micro-mirrors with controlled amplitude and phase

This paper describes the fabrication of circular micro-mirrors with diameters between 50 and 150 µm with controlled amplitude and phase. Design, manufacturing and characterization method are presented.

Single resonance monolithic Fabry-Perot filters formed by volume Bragg gratings and multilayer dielectric mirrors

High efficiency reflecting volume Bragg gratings (VBGs) recorded in PTR glass plates have shown un-preceded performances that make them very good candidates for narrowband spectral filtering with sub-nanometer spectral widths. However, decreasing the bandwidth to value below 30-50 pm is very challenging as it requires increasing the thickness of the RBG to more than 15-20 mm. To overcome this limitation, we propose a new approach which is a monolithic Fabry-Perot cavity which consists from a reflecting VBG with a multilayer dielectric mirror (MDM) deposited on its surface. A VBG with a grating vector perpendicular to its surface and a MDM produce a Fabry-Perot resonator with a single transmission band inside of the reflection spectrum of the VBG. We present a theoretical description of this new class of filters that allow achieving a single ultra-narrowband resonance associated with several hundred nanometers rejection band. Then we show the methods for designing and fabricating such filter. Finally, we present the steps that we followed in order to fabricate a first prototype for 852 nm and 1062 nm region that demonstrates a 30 pm bandwidth, 90+% transmission at resonance and a good agreement with theoretical simulation.

Laser Damage Resistance of HfO 2 Thin Films Deposited by Electron Beam Deposition, Reactive Low Voltage Ion Plating and Dual Ion Beam Sputtering

We study the laser damage resistance at 1064 and 355nm of HfO2 thin films deposited by three different processes in various conditions. We compare their Laser Induced Damage Threshold obtained trough several measurement procedures.