BIOTECHNOLOGY
According to Dr. McCusker, one of
the primary areas of research relates to solar energy conversion. Transition metal complexes are an important class of molecules in this field of research and can be studied using time-resolved spectroscopy to examine the thermodynamics and conversion efficiencies of solar cells, the potential use of alternative and less expensive earth-abundant materials for processes that can achieve light-to-chemical energy conversion, and for designing molecules whose excited-state properties will enable their use in a wide range of such compounds to enable new kinds of organic transformations of potential interest in the pharmaceutical industry. “We are pursuing a systematic
examination of chemical perturbations to excited-state electronic and geometric structure,” said Dr. McCusker. “As a result, we will be able to develop a comprehensive picture of how transition metal chromosphores absorb and dissipate energy.”
GETTING ON THE RIGHT WAVELENGTH To facilitate this type of research,
fast, pulsed lasers are required to selectively excite a molecule to a specific state to study the compound’s excited-state properties. In the early days of laser development, lasers were constructed to operate at very specific wavelengths. Single wavelength Nd:YAG lasers, for example, are inexpensive and simple to use. However, additional hardware is required to modify a 1064-nm laser before it can operate at a different harmonic frequency for testing such as 213, 266, 355 and 532 nm. This adds to the cost of the laser. “There are gaps between the
wavelengths, and the jump between 1064 nm to 532 nm is significant,” said Dr. Mark Little, technical and scientific consultant for Opotek, adding that testing each of those harmonics increases the cost. The Carlsbad, California-based Opotek offers solutions for specialised applications including photoacoustic, diagnostics, hyperspectral imaging, and medical research. According to Little, OPO lasers can
convert the fundamental wavelength of pulsed mode Nd:YAGs to a selected
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frequency This tunability enables OPOs to generate light in a broad range of wavelengths that are amplified within the OPO for a usable output beam. Dr. McCusker and his research
group use the Vibrant 355 II Nd:YAG- pumped OPO laser from Opotek which can quickly provide a tunable wavelength output from 300-2400 nm and is used for both time-resolved absorption and time-resolved emission requirements. Dr. McCusker has relied exclusively
on their OPO lasers for the portion of his research program focused on nanosecond time-resolved spectroscopy since 1995 when he was an assistant professor at UC Berkeley.
REACHING INTO DEEP UV Much of the research conducted by Dr. McCusker and his team, such as solar energy conversion studies, involves designing and synthesising molecules that absorb light in the visible part of the spectrum. However, he notes that for organic
carbon-based or aromatic compounds, researchers may want to study
t❝To facilitate this ype of research,
fast, pulsed lasers are required to selectively excite a molecule to a specific state to study the compound’s excited state properties.
UV damage to DNA. Since DNA is composed of organic base pairs that absorb in the ultraviolet spectrum rather than the visible spectrum, OPO lasers are required to access those ultraviolet wavelengths for the study of these compounds. n
For more information visit
https://www.opotek.com/
Opotek’s lazers are solid-state and do not require expensive consumables
More on Opotek Opotek has developed a diverse array of OPO technologies that ensures
wavelengths from the mid-infrared to deep UV can easily be produced. OPO lasers can be designed to generate wavelengths down to 190 nanometers through multiple stages of optical conversion Moreover, unlike typical fixed wavelength deep ultraviolet (UV) lasers, OPO lasers are solid-state and so do not require expensive consumables such as specialised gas or chemical mixtures as the lasing medium.
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