Broadband Multiple-Plate Continuum Light Source for Ultrafast Transient Absorption Studies of Organic Upconversion Devices

Bo-Han Chen^1*, Chun-Jen Shih^2,4, Chao-Yang Lin³, Kai Chen³, Chih-Hsuan Lu¹, Shang-Da Yang¹, Jiun-Haw Lee², Shun-Wei Liu⁴

¹光電工程研究所, 國立清華大學, 新竹市, Taiwan
²電子工程學研究所, 國立臺灣大學, 台北市, Taiwan
³Robinson Research Institute, Victoria University of Wellington, Wellington, New Zealand
⁴有機電子研究中心, 明志科技大學, 新北市, Taiwan

* Presenter:Bo-Han Chen, email:bohan.chen@ee.nthu.edu.tw

The ability to probe ultrafast carrier dynamics is essential for advancing organic photoelectronics, where charge generation, separation, and recombination processes occur on femtosecond to nanosecond timescales. In this presentation, I will introduce our development of a multiple-plate continuum (MPC) light and its integration into a broadband transient absorption (TA) spectroscopy system, forming a powerful platform for investigating organic photodetectors (OPDs) and organic upconversion devices (OUDs).
We have demonstrated that the MPC scheme, based on the nonlinear Kerr effect through a sequence of thin glass plates, produces bright, stable, and octave-spanning white-light continua extending from the visible to the near-infrared region. When combined with careful pulse compression, this source provides excellent temporal resolution and spectral coverage ideally suited for ultrafast pump-probe spectroscopy. Compared with conventional bulk or photonic crystal fiber-based continua, the MPC delivers higher spectral density, enhancing the detection signal-to-noise ratio in broadband ultrafast spectroscopy.
By employing this light source in a home-made TA setup, we were able to study the fundamental processes governing OUD performance. The measurements revealed efficient exciton dissociation, field-assisted charge separation, and prolonged carrier lifetimes under bias. These phenomena provide direct spectroscopic evidence for the strong responsivity of OPDs and the high photon-to-photon upconversion efficiency of OUDs.
In summary, I will present how the combination of bright MPC-based ultrashort pulses with TA spectroscopy creates new opportunities for studying organic photoelectronic materials and devices. This synergy not only clarifies the mechanisms underpinning current device performance but also establishes a framework for guiding the design of next-generation infrared detection and upconversion technologies.

Keywords: Ultrafast optics, Nonlinear optics, Transient absorption, Organic Upconversion Device