Chapter 29
Femtosecond Pump-Probe
Microspectroscopy and Its Application
to Single Organic Nanoparticles
and Microcrystals
Yukihide Ishibashi and Tsuyoshi Asahi
Abstract A novel femtosecond pump-probe microspectroscope using a
femtosecond Ti:Sapphire oscillator as a light source was developed. The fundamental specifications are the temporal resolution of 350 fs, the spatial resolution
of 770 nm, and the tunable probe wavelength in the region from 500 to 900 nm.
The setup has two modes of the probe light detection; one is back-scattered light
detection and another conventional transmitted light detection. The back-scattering
mode measurement demonstrated about 20-times higher gain of the transient signal
of single nanoparticles compared to the conventional transmittance-mode one. This
high-sensitivity enables the single nanoparticle ultrafast spectroscopy of organic
nanomaterials which in general are low photo-durability. The femtosecond pumpprobe microspectroscopy is fruitful in the researches of solid-state photochemical
processes characterized by restricted molecular motions and intermolecular electronic interactions in the confined space. The potential applications of the developed
microspectroscopic system are demonstrated for the picosecond excited state
dynamics of nm- to μm-sized organic crystals.
Keywords Femtosecond pump-probe spectroscopy · Nanospectroscopy · Single
organic nanoparticle · Excited-state dynamics
29.1 Introduction
Over the past two decades, organic nanoparticles have been attracted in a scientific and technological area of materials because they combine molecular properties
with nanoparticle characteristics such as optical, electronic, and solubility properties
depending on their size and shape. The nanoparticles having the dimension of several
Y. Ishibashi · T. Asahi (B)
Department of Materials Science and Biotechnology, Graduate School of Science and
Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
e-mail: asahi.tsuyoshi.mh@ehime-u.ac.jp
Y. Ishibashi
e-mail: ishibashi.yukihide.mk@ehime-u.ac.jp
© Springer Nature Singapore Pte Ltd. 2020
H. Miyasaka et al. (eds.), Photosynergetic Responses in Molecules
and Molecular Aggregates, https://doi.org/10.1007/978-981-15-5451-3_29
493
Femtosecond Pump-Probe
Microspectroscopy and Its Application
to Single Organic Nanoparticles
and Microcrystals
Yukihide Ishibashi and Tsuyoshi Asahi
Abstract A novel femtosecond pump-probe microspectroscope using a
femtosecond Ti:Sapphire oscillator as a light source was developed. The fundamental specifications are the temporal resolution of 350 fs, the spatial resolution
of 770 nm, and the tunable probe wavelength in the region from 500 to 900 nm.
The setup has two modes of the probe light detection; one is back-scattered light
detection and another conventional transmitted light detection. The back-scattering
mode measurement demonstrated about 20-times higher gain of the transient signal
of single nanoparticles compared to the conventional transmittance-mode one. This
high-sensitivity enables the single nanoparticle ultrafast spectroscopy of organic
nanomaterials which in general are low photo-durability. The femtosecond pumpprobe microspectroscopy is fruitful in the researches of solid-state photochemical
processes characterized by restricted molecular motions and intermolecular electronic interactions in the confined space. The potential applications of the developed
microspectroscopic system are demonstrated for the picosecond excited state
dynamics of nm- to μm-sized organic crystals.
Keywords Femtosecond pump-probe spectroscopy · Nanospectroscopy · Single
organic nanoparticle · Excited-state dynamics
29.1 Introduction
Over the past two decades, organic nanoparticles have been attracted in a scientific and technological area of materials because they combine molecular properties
with nanoparticle characteristics such as optical, electronic, and solubility properties
depending on their size and shape. The nanoparticles having the dimension of several
Y. Ishibashi · T. Asahi (B)
Department of Materials Science and Biotechnology, Graduate School of Science and
Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
e-mail: asahi.tsuyoshi.mh@ehime-u.ac.jp
Y. Ishibashi
e-mail: ishibashi.yukihide.mk@ehime-u.ac.jp
© Springer Nature Singapore Pte Ltd. 2020
H. Miyasaka et al. (eds.), Photosynergetic Responses in Molecules
and Molecular Aggregates, https://doi.org/10.1007/978-981-15-5451-3_29
493