This simple process holds to obtain a dried film of SWCNT in bundles, which has already been structurally analyzed by Raman spectroscopy and scanning tunneling microscopy [11] For
M-SWCNT way, 10 mg of pristine SWCNT powder was added to 20 ml of 2%-sodium-cholate water solution, then sonicated for 1 h, and finally centrifuged at 25,000×g for 1 h; the upper suspension layer was dropped on a glass substrate, leading to a few microns-thick SWCNT film. We already reported the linear absorption spectra of both samples in [10], which indicate that the SWCNT first excitonic transition Selleckchem Y 27632 energies are suitable for 1,550-nm-window photonics applications. Results and discussion Comparison of SWCNT and MQW nonlinear optical properties for passive photonics applications: buy GSK3235025 pump-probe experiments In order to compare SWCNT with MQW optical property performances for saturable absorption and optical switching applications, pump-probe experiments are performed at 1,550 nm with femtosecond optical excitation, and probe pulses
originated from an optical parametric oscillator. Details of the experimental setup are provided in [10]. We already demonstrated the ultrafast absorption dynamics of SWCNT in direct comparison with MQW [7] and pointed out the B-SWCNT faster recovery time of absorption dynamics as a great asset of these 1D nanomaterials for ultrafast photonics. Another important key parameter for SA applications is the amplitude of SA nonlinearities, which are characterized by such pump-probe experiments, thanks to the measurement of normalized differential transmission (NDT), defined as NDT = ΔT/T 0 = (T – T 0)/T 0, where T 0 and T are the transmission of the probe at very low and high pump excitation fluences, respectively. NDTs for B-SWCNT,
M-SWCNT, and MQW as a function of incident pump fluence at 1550-nm excitation wavelength are demonstrated in Figure 1. Whereas, B-SWCNT and MQW NDTs are closely the same; for a given incident pump fluence, the amplitude of M-SWCNT NDT is clearly greater than B-SWCNT and MQW NDTs (six times greater at 10 μJ cm-2, for example). This enhancement of 1D excitonic nonlinearities in M-SWCNT PtdIns(3,4)P2 is associated with a reduction of tube-tube interactions, thanks to micelles environment of SWCNT, and contributes to better expected performances of SWCNT-based devices for passive photonics applications. In addition to fast response time and strong nonlinearity as key requirements for nonlinear materials, the power consumption has to be as low as possible, for general energy consumption control in future photonics [3]. The power consumption is related to the input fluence required for inducing a switching phenomenon of nonlinear materials, called saturation fluence F S.