Effects of finite beam size and crossing angle on space–time–frequency-resolved pump–probe spectroscopy of optically transparent materials

2003 ◽  
Vol 228 (1-3) ◽  
pp. 187-200
Author(s):  
J.Y. Zhou ◽  
H.Y. Sang ◽  
J. Cheng ◽  
J. Lin ◽  
Z.R. Qiu ◽  
...  
2015 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Nur Farahiah Ibrahim ◽  
Zahari Abu Bakar ◽  
Azlina Idris

Channel estimation techniques for Multiple-input Multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) based on comb type pilot arrangement with least-square error (LSE) estimator was investigated with space-time-frequency (STF) diversity implementation. The frequency offset in OFDM effected its performance. This was mitigated with the implementation of the presented inter-carrier interference self-cancellation (ICI-SC) techniques and different space-time subcarrier mapping. STF block coding in the system exploits the spatial, temporal and frequency diversity to improve performance. Estimated channel was fed into a decoder which combined the STF decoding together with the estimated channel coefficients using LSE estimator for equalization. The performance of the system was compared by measuring the symbol error rate with a PSK-16 and PSK-32. The results show that subcarrier mapping together with ICI-SC were able to increase the system performance. Introduction of channel estimation was also able to estimate the channel coefficient at only 5dB difference with a perfectly known channel.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 312
Author(s):  
Yusuf Tutel ◽  
Gökhan Sevinç ◽  
Betül Küçüköz ◽  
Elif Akhuseyin Yildiz ◽  
Ahmet Karatay ◽  
...  

Meso-substituted borondipyrromethene (BODIPY)-porphyrin compounds that include free base porphyrin with two different numbers of BODIPY groups (BDP-TTP and 3BDP-TTP) were designed and synthesized to analyze intramolecular energy transfer mechanisms of meso-substituted BODIPY-porphyrin dyads and the effect of the different numbers of BODIPY groups connected to free-base porphyrin on the energy transfer mechanism. Absorption spectra of BODIPY-porphyrin conjugates showed wide absorption features in the visible region, and that is highly valuable to increase light-harvesting efficiency. Fluorescence spectra of the studied compounds proved that BODIPY emission intensity decreased upon the photoexcitation of the BODIPY core, due to the energy transfer from BODIPY unit to porphyrin. In addition, ultrafast pump-probe spectroscopy measurements indicated that the energy transfer of the 3BDP-TTP compound (about 3 ps) is faster than the BDP-TTP compound (about 22 ps). Since the BODIPY core directly binds to the porphyrin unit, rapid energy transfer was seen for both compounds. Thus, the energy transfer rate increased with an increasing number of BODIPY moiety connected to free-base porphyrin.


1994 ◽  
Vol 61 (1-3) ◽  
pp. 153-165 ◽  
Author(s):  
Robert M. Whitnell ◽  
Kent R. Wilson ◽  
YiJing Yan ◽  
Ahmed H. Zewail

2013 ◽  
Vol 88 (6) ◽  
pp. 065404 ◽  
Author(s):  
Niharika Singh ◽  
Ayan Ray ◽  
R D'Souza ◽  
Q V Lawande ◽  
B N Jagatap

Biochemistry ◽  
1993 ◽  
Vol 32 (29) ◽  
pp. 7512-7518 ◽  
Author(s):  
Sergei Savikhin ◽  
Todd Wells ◽  
Pill Soon Song ◽  
Walter S. Struve

2012 ◽  
Vol 70 (4) ◽  
pp. 1363-1372
Author(s):  
Wei Song ◽  
S. P. Balakannan ◽  
Moon Ho Lee

Sign in / Sign up

Export Citation Format

Share Document