Three-photon absorption for nanosecond excitation in cadmium selenide quantum dots

Abstract

We experimentally observe saturable absorption and dramatic three-photon absorption in various colloidal solutions of cadmium selenide quantum dots, with a strong size dependence witnessed for these properties. We also develop a model for the electronic portion of the nonlinearities that illustrates well the trends exhibited by our experimental data. The model incorporates six bands ͑three each in the valence and conduction bands͒.

Three-Photon Absorption in Zno Film Using Ultra Short Pulse Laser

“…The absorption is through a virtual-states that assists the inter band transitions. This transition produces electron-hole pairs in the excited states and, subsequently, the band-edge emission via their radiative recombination [9]. The two photon absorption (2PA) in semiconductor nanocrystals (NCs) has been widely investigated [8,10], while the research effort on their three-photon absorption (3PA) is limited [11].…”

Three-photon excitation of quantum dots with a telecom-band ultrafast fiber laser

“…The experimental data for three-photon excitation shows that there are no significant changes or shifts in the fluorescence spectrum compared to the linear excitation case, and the third order dependence on excitation power shows that the quantum dot sample is indeed excited through a three-photon process. The process in the study by Horton et al [17] could thus be replicated using quantum dots as a more favourable label agent [7,8,10,11].…”

“…Compared to other fluorescent molecules, quantum dots possess high brightness, low bleaching rate and absorption over a wide wavelength range [7,8]. Similar to the fluorescence from other labels, quantum dot fluorescence can be driven by both single-and multiphoton processes [9][10][11][12][13].…”

“…They found that an optimum wavelength window due to scattering and absorption in tissue lies close to the telecom band. Quantum dots are attractive for use in such applications due to their large three-photon absorption cross-section [10,11].…”

Backward stimulated Bragg scattering in multiphoton active CdTexSe1−x quantum dots system

“…[11][12][13][14][15][16][17][18][19][20][21] Both MPA and backward SBgS are intensitydependent nonlinear processes; they can be combined to realize an enhanced optical power limiting performance. [11][12][13][14][15][16][17][18][19][20][21] Both MPA and backward SBgS are intensitydependent nonlinear processes; they can be combined to realize an enhanced optical power limiting performance.…”