Materials characterization is used to understand the microscopic structure and properties of materials. A material's structure and properties are charaterized by probing and measuring them using microscopy and spectroscopy techniques.
Reliable methods for determining the nonlinear optical properties of materials (i.e. nonlinear absorption and nonlinear refraction) have been developed for wide ranging applications such as optical limiting, multi-photon polymerization as well as optical switching. Of these methods, “z-scan”, developed by Eric Van Stryland, remains the standard technique.
The z-scan technique is performed by translating a sample through the beam waist of a focused beam and then measuring the power transmitted through the sample. The two measurable quantities connected with the z-scan are nonlinear absorption (NLA) and nonlinear refraction (NLR). These parameters are associated with the imaginary and real part of the third order nonlinear susceptibility, χ(3), and provide important information about the properties of the material.
The Z-SCAN Characterization of Transparent Optical Materials Kit is a simple implementation of the z-scan technique that can be used to characterize relatively thin (< 5 mm) optical materials. All of the optics and mounts in this kit have been certified by our Ph.D. scientists in the Newport Technology and Applications Center to work together and be compatible with the Spitfire XP Pro.
Ultrafast Photoacoustic characterization is a spectroscopic technique that exploits the photoacoustic effect and ultra-fast laser technology to study materials at the nanometer scale. The photoacoustic effect is an astonishing accomplishment of science. It relies on incident light to cause local thermal excitations in a sample which then creates acoustic waves. This technique has been advancing with the development of ultrafast spectroscopy in recent years.
When an ultrafast laser pulse is directed at a highly absorbing target, the entire pulse energy is absorbed by a thin surface layer of just a few nanometers, resulting in intense local heating. If the material is a metal, the interface layer will undergo rapid expansion,creating a high frequency acoustic shock wave. Researchers realized that these photo-duced acoustic wavescould be used to perform Sound Navigation and Ranging (SONAR) with a dramatically improved spatial/temporal resolution. For example, layer thickness in integrated circuits can be determined by the time delay of the returning acoustic echo from the interfaces between material layers.
Ultrafast Photoacoustic Characterization Solutions
Newport IMS-LM Series High Performance Linear Stages meet all the requirements of the application, offering superior accuracy. As the photo-induced sample excitation occurs on the femto to nanosecond scale before generating the acoustic wave, electronics triggering and synchronization become critical in the process. For this reason, an ability to send an external trigger signal based on position provides an added benefit for time-resolved experiments. Our XPS Universal Motion Controller features the Position Compare Output (PCO) for the precise triggering of external devices with the extremely low latency of 50 ns.
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