Gate-controlled generation of optical pulse trains using individual carbon nanotubes

Abstract

In single-walled carbon nanotubes, electron–hole pairs form tightly bound excitons because of limited screening. These excitons display a variety of interactions and processes that could be exploited for applications in nanoscale photonics and optoelectronics. Here we report on optical pulse-train generation from individual air-suspended carbon nanotubes under an application of square-wave gate voltages. Electrostatically induced carrier accumulation quenches photoluminescence, while a voltage sign reversal purges those carriers, resetting the nanotubes to become luminescent temporarily. Frequency-domain measurements reveal photoluminescence recovery with characteristic frequencies that increase with excitation laser power, showing that photoexcited carriers provide a self-limiting mechanism for pulsed emission. Time-resolved measurements directly confirm the presence of an optical pulse train synchronized to the gate voltage signal, and flexible control over pulse timing and duration is also demonstrated. These results identify an unconventional route for optical pulse generation and electrical-to-optical signal conversion, opening up new prospects for controlling light at the nanoscale.

Super-resolution fluorescence imaging of carbon nanotubes using a nonlinear excitonic process

“…Photoluminescence Microscopy. A homebuilt confocal microscopy system is used to perform PL measurements at room temperature [11,[30][31][32]. A wavelengthtunable Ti:sapphire laser is used for excitation after controlling its power and polarization by neutral density filters and a half-wave plate, respectively.…”

Pulsed ultra-violet laser interactions with ultra-low-density porous carbon nanotube sponges

“…optoelectronic, mechanical and electrical carrier transportation properties as compared to bulk materials [18][19][20][21]. As a result, the interactions of nano-material with electric fields and light have been observed to differ from those with the bulk materials [22][23][24][25][26]. A particular interesting question still remains for how pulsed UV lasers interact with nanostructured materials and generates the plasma from a fundamental aspect.…”

Tunable electronic correlation effects in nanotube-light interactions

“…Nanotubes thus offer an ideal platform for the fundamental studies of the many-body interactions and their impact on the optical spectra of photoexcited quasi-1D systems [2][3][4][5][6][7][8][9]. Knowledge of the underlying optical response of nanotubes under carrier doping is also of great importance for the * miyauchi@iae.kyoto-u.ac.jp † tony.heinz@columbia.edu development of electrically tunable optoelectronic devices [11][12][13]56,59] that operate at room temperature and on the nanometer length scale. For a complete understanding of the impact of many-body electronic correlation effects on the optical response, it is highly desirable to observe broadband optical response of clean and isolated 1D nanostructures over a wide range of free-carrier densities.…”