Nanosecond Z-Scan Measurements of Optical Nonlinearities in 5CB and CB15 at 532 Nm

ABSTRACTWe have measured extremely large second hyperpolarizabilities〈γxxxx〉 in solutions of two recently prepared organic polymer semiconductor superlattices. These block copolymers are of alternating aromatic and quinoidal moieties and structurally differ by a side group substituent. The values observed are 1.6 × 10−29 esu for the parent copolymer (PBTBQ) and 3.7 × 10−30 esu for its acetoxy derivative (PBTABQ). The corresponding values of χ(3) are estimated to be 2.7 × 10−7 esu and 4.5 × 108 esu. The measurements, made by picosecond degenerate four wave mixing at 532 nm, showed that the dynamics of the larger χ(3) valued copolymer were faster than the 30 ps resolution of the instrument while the derivative exhibited a slower response. The large magnitude and rapid response of the cubic optical nonlinearities in these novel materials suggest theiT potential for further development and photonic device applications.

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Dynamic saturable optical nonlinearities in free base tetrapyridylporphyrin

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424603000586 ◽

2003 ◽

Vol 07 (06) ◽

pp. 452-456 ◽

Cited By ~ 16

Author(s):

Newton M. Barbosa Neto ◽

Leonardo De Boni ◽

José J. Rodrigues ◽

Lino Misoguti ◽

Cléber R. Mendonça ◽

...

Keyword(s):

Excited States ◽

Cross Sections ◽

Saturable Absorption ◽

Reverse Saturable Absorption ◽

Optical Nonlinearities ◽

Free Base ◽

Photophysical Parameters ◽

Crossing Time ◽

532 Nm

Dynamic optical nonlinearities in free base tetrapyridylporphyrin ( H 2 TPyP ) solutions were investigated at 532 nm with the Z-scan technique. We observed a reverse saturable absorption process that was found to have a fast contribution related to the singlet population and a slow accumulative contribution arising from the triplet population. The optical excitations and subsequent relaxations can be interpreted with a five-energy-level diagram that allows determination of the excited states photophysical parameters such as triplet and singlet absorption cross-sections and the intersystem crossing time.

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Optical nonlinearities and optical limiting in GaP at 532 nm

10.1117/12.138062 ◽

1992 ◽

Cited By ~ 5

Author(s):

Steven J. Rychnovsky ◽

Graham R. Allan ◽

Clark H. Venzke ◽

Arthur L. Smirl ◽

Thomas F. Boggess

Keyword(s):

Optical Limiting ◽

Optical Nonlinearities ◽

532 Nm

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INVESTIGATION OF NEAR TWO-PHOTON RESONANCE OPTICAL NONLINEARITIES IN Ni(Ac)2[N-(8-QUINOLYL) PYRIDINE-2-CARBOXAMIDE] · 4H2O BY THE Z-SCAN TECHNIQUE

Journal of Nonlinear Optical Physics & Materials ◽

10.1142/s0218863503001225 ◽

2003 ◽

Vol 12 (01) ◽

pp. 81-89 ◽

Cited By ~ 1

Author(s):

SHENG-LI GUO ◽

HUI-TIAN WANG ◽

N. B. MING ◽

JUN-YONG ZHANG ◽

ZHI-JIAN GUO

Keyword(s):

Nonlinear Absorption ◽

Nonlinear Refraction ◽

Photon Absorption ◽

Closed Aperture ◽

Optical Nonlinearities ◽

Two Photon Absorption ◽

Two Photon ◽

Nonlinear Optical Absorption ◽

532 Nm ◽

Photon Resonance

We describe a modified Z-scan technique for the case when nonlinear refraction is accompanied by nonlinear absorption to separately evaluate the nonlinear refraction and the nonlinear absorption by performing straightforward measurements with the aperture removed. We divide the closed aperture (S < 1) normalized Z-scan by a scan with an open aperture (S = 1). With nanosecond scale at a 532 nm wavelength, we first measured the nonlinear optical absorption and refraction coefficients of a solution of Ni(Ac)2[N-(8-quinolyl) pyridine-2-carboxamide] · 4H2O by using the modified Z-scan technique. The nonlinear absorption originates from the near resonant two-photon absorption while the mechanism of the nonlinear refraction is the near resonant two-photon absorption transition enhancement. The linear increasing dependences of the optical nonlinearities on the incident irradiance arise from the population redistribution due to the near resonant two-photon absorption.

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