The Center for Advanced Photonics Research at Temple University focuses on understanding the photochemistry and photophysics of molecules interacting with ultrafast, ultra-intense laser pulses. "Ultrafast" means laser pulses that are only a few millionths of a billionth of a second, with our shortest pulses approaching just 5 femtoseconds in duration. "Ultra-intense" means laser fields approaching the electric field strengths binding electrons within molecules. The combination of these two properties creates environments that are unique in the universe and thus new phenomena arise. Since 1991 we have been discovering and understanding such new phenomena, an area that we call strong-field chemistry.
Current research areas at the Center for Advanced Photonics Research include laser vaporization of condensed phase systems, laser filamentation in air, laser-based synthesis and processing of nanomaterials in the solution, solid, and gas phases, control of chemical reactions using shaped laser pulses, elucidation of the evolution of laser-generated plasmas and control of strong-field, time-dependent Rabi oscillation. These efforts are leading to new ways to diagnose disease, map cellular components, classify tissues and phenotype, detect improvised explosive devices, classify explosives for forensics analysis, and to synthesize novel, narrowly-dispersed nanomaterials.
The Center for Advanced Photonics Research is a multidisciplinary organization that includes eight faculty actively collaborating from disciplines including physical, analytical and inorganic chemistry, and theoretical and experimental physics. Graduate and undergraduate students are drawn from all areas of science to form research teams to address questions including:
Nanomaterials by design:
Laser Vaporization Mass Spectrometry:
- Can we produce new nanomaterials (quantum dots, metallic alloys, nanodiamond) using non-equilibrium energy deposition by shaped laser pulses?
- Can we map molecular signatures and biomarkers in cells on the sub-micron scale?
- What is the transfer mechanism of biomolecules, including proteins and viruses, from the solid state into the gas phase upon laser vaporization?
- Can we access top down protein sequencing by charging proteins beyond the supercharging limit?
- Can we develop gas phase spectroscopic methods that are sensitive enough to detect trace signatures in air at the part per billion level for detecting improvised explosive devices and signatures of radioactive materials?
- What are fundamental nonlinearities important for laser filamentation?
- Can we calculate the nonlinear properties of nitrogen and oxygen neutrals and ions to enable first principles nonlinear propagation calculations for laser filamentation?
Laser Control of Chemical Reactions:
- What are the limits of laser control of chemical reactivity and what are the mechanisms of strong field control?
- Will the control of chemical reactivity increase when the molecule is ionized prior to application of the control pulse?
- Can we measure the electronic spectra of radical cations?
Time-Dependent Rabi Oscillation:
- Can we phase match the broad bandwidth emission from the time-dependent Rabi oscillation to form a new laser source?
- What is the evolution of the initial electron dynamics after strong field ionization in air?