RESUMO
We present in this article the complete setup to build a triggered controller with a mechanical optical shutter. The system is a low cost, Do-It-Yourself, and easy to implement setup with three functionalities: Manual mode, direct mode with TTL signal command and Triggered mode with a TTL signal command. Our setup is primarily intended to be integrated in optical setup where one needs to control the opening time of a light path, but can be used also for any other setup where one wants to send a TTL signal to command another subsystem (in our case the shutter is that subsystem). The shutter used here is hard disk drive voice-coil actuator, which was already demonstrated to have interesting potentialities to be a mechanical shutter. In the Manual mode, this setup achieves an opening and closing time of 3 ms. In Direct mode with TTL signal command, the setup has a delay response time of 19 ms and a minimum open pulse time of 23 ms. This low cost device which can be made with less than 50, have similar characteristics with commercial ones which can be twenty times more expensive.
RESUMO
We investigate phase imaging as a measurement method for laser damage detection and analysis of laser-induced modification of optical materials. Experiments have been conducted with a wavefront sensor based on lateral shearing interferometry associated with a high-magnification optical microscope. The system has been used for the in-line observation of optical thin films and bulk samples, laser irradiated in two different conditions: 500 fs pulses at 343 and 1030 nm, and millisecond to second irradiation with a CO2 laser at 10.6 µm. We investigate the measurement of the laser-induced damage threshold of optical material by detection and phase changes and show that the technique realizes high sensitivity with different optical path measurements lower than 1 nm. Additionally, the quantitative information on the refractive index or surface modification of the samples under test that is provided by the system has been compared to classical metrology instruments used for laser damage or laser ablation characterization (an atomic force microscope, a differential interference contrast microscope, and an optical surface profiler). An accurate in-line measurement of the morphology of laser-ablated sites, from few nanometers to hundred microns in depth, is shown.
RESUMO
We report on the realization of aluminum oxyfluoride thin films and alumina/silica mixture coatings with different ratios by ion beam sputtering. The atomic compositions quantified by energy dispersive x-ray spectroscopy are correlated with the optical properties calculated from spectrophotometry and laser calorimetry measurements. Furthermore, the femtosecond laser damage resistance (τ=400 fs) of single layers is investigated in the infrared at 1030 nm and in the ultraviolet at 343 nm wavelengths. Experimental results on the wavelength scaling of the laser-induced damage threshold for oxyfluoride and oxide composite coatings are presented.
