Del Mar Photonics

A PHOTOPHYSICAL INVESTIGATION OF NICKEL TETRAPYRROLE MACROCYCLES (pdf)
 

ANDREY V. ZAMYATIN, Del Mar Photonics,Inc., 4119 Twilight Ridge, San Diego, CA 92130;
MICHAEL A.J. RODGERS, Center for Photochemical Sciences, Department of Chemistry, Bowling Green
State University, Bowling Green, Ohio, 43403.
 

The porphyrins are an important class of chromophores with high stability and ef cient light absorption ability in the visible and
near-infrared regions of the optical spectrum. Porphyrins have a set of highly delocalized 􀀀 -orbitals situated on the carbon-nitrogen
framework. When such a ligand is coordinated to a centrally-located metal atom of the transition series, having incompletely lled
d-orbitals (Ni, Co, Fe, Cu, etc.), the 􀀀 - and d-manifolds can interact. As a result the excited state deactivation dynamics becomes very
dependent on the electronic nature of the central metal. This work has two major parts. The rst part focuses on the investigation of dual
excited states of some Ni(II) porphyrins. Dual excited states are molecular entities that have absorbed two successive photons to generate
molecular states with electronic excitation in two distinct regions of the metalloporphyrin. The dual excited states were studied by means
of femtosecond two-pump-one-probe transient absorption spectroscopy. Two successive pulses of 400 nm and 550 nm were used for
excitation. Based on the kinetic and spectral information of the observed transients we propose a mechanism for the Ni(II) porphyrin dual
excited state deactivation involving formation of an intramolecular charge transfer state. The second part concerns the photophysical
studies of Ni(II) meso-tetraphenyl tetrabenzoporphyrin (NiTPTBP). The excited states metal-ligand dynamics of Ni(II)TPTBP have
been investigated using time-resolved absorption spectroscopy in different solvents. The DFT computations revealed the presence of
two ligand-to-metal charge transfer states located close in energy to the (d,d) state. These LMCT states are responsible for the lifetime
dependence on solvent polarity. Upon photoexcitation two competing processes depopulate the porphyrin lowest singlet excited state
S

. One involves the charge transfer states manifold and another involves the metal excited state manifold

 

Ultrafast Dynamics Research Tools

Beacon femtosecond fluorescence up-conversion (optical gating) spectrometer
Hatteras Ultrafast Transient Absorption Spectrometer

Femtosecond Lasers

Trestles femtosecond Ti:Sapphire laser
Trestles Finesse femtosecond Ti:Sapphire laser with integrated DPSS pump laser
Teahupoo Rider femtosecond amplified Ti:Sapphire laser
Mavericks femtosecond Cr:Forsterite laser
Tamarack femtosecond fiber laser (Er-doped fiber)
Buccaneer femtosecond OA fiber laser (Er-doped fiber) and SHG
Cannon Ultra-broadband light source
Tourmaline femtosecond Yb-doped fiber laser
Chata femtosecond Cr:ZnSe laser (2.5 micron) coming soon

Femtosecond pulse measurement instrumentation

Reef scanning and single shot femtosecond autocorrelators
Avoca SPIDER
Spectral phase interferometry for direct electric-field reconstruction (SPIDER)
Rincon third order femtosecond cross-correlator (third order autocorrelator TOAC) also referred to as contrastmeter

High Power Femtosecond Laser Systems

Cortes 800 tabletop 40 TW Ti:Sapphire laser system
Cortes E  - High vacuum laser ablation/deposition system with 2 TW Ti:Sapphire laser
Cortes K - femtosecond seed laser for Petawatt KrF excimer laser
Cortes O 200TW femtosecond laser - KD*P CPOPA based amplifier system
Jaws femtosecond Cr:forsterite Multi-Terawatt Amplified Laser
High-vacuum system for laser ablation/deposition

Femtosecond Systems and Accessories

Femtosecond Micromachining
Femtosecond nanophotonics
Femtosecond NSOM
Pacifica femtosecond fiber laser based terahertz spectrometer
Pismo pulse picker (ultrafast electro-optical shutter)
Wavelength conversion: second and third harmonics generators for femtosecond lasers
Jibe white light continuum generator
Kirra Optical Faraday Rotators and Isolators
Deformable mirrors - active elements for adaptive optics systems
ShaH - the family of fast, accurate and reliable wavefront sensors
Complete adaptive optics systems
Faraday rotators and isolators for high-power (up to 1kW) laser beams
SAM - Saturable Absorber Mirrors
PCA - Photoconductive antenna for terahertz applications
Passive Q-switches based on Co2+:ZnS, Cr2+:ZnS and Cr2+:ZnSe
Lithium Niobate Q-switches
Lithium Tantalate Q-switches

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