Pulse duration adjusted by changing the cavity length with a multi-pass cavity in a Q-switched Nd:YAG laser

2019 ◽  
Vol 44 (18) ◽  
pp. 4471 ◽  
Author(s):  
Yan-Jie Song ◽  
Ke Liu ◽  
Nan Zong ◽  
Wei Tu ◽  
Yong Bo ◽  
...  
2019 ◽  
Vol 7 (4) ◽  
pp. 99 ◽  
Author(s):  
Namour ◽  
El Mobadder ◽  
Magnin ◽  
Peremans ◽  
Verspecht ◽  
...  

Peri-implantitis (PI) is an inflammatory disease of peri-implant tissues, it represents the most frequent complication of dental implants. Evidence revealed that microorganisms play the chief role in causing PI. The purpose of our study is to evaluate the cleaning of contaminated dental implant surfaces by means of the Q-switch Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser and an increase in temperature at lased implant surfaces during the cleaning process. Seventy-eight implants (titanium grade 4) were used (Euroteknika, Sallanches, France). Thirty-six sterile implants and forty-two contaminated implants were collected from failed clinical implants for different reasons, independent from the study. Thirty-six contaminated implants were partially irradiated by Q-switch Nd:YAG laser (1064 nm). Six other contaminated implants were used for temperature rise evaluation. All laser irradiations were calibrated by means of a powermetter in order to evaluate the effective delivered energy. The irradiation conditions delivered per pulse on the target were effectively: energy density per pulse of 0.597 J/cm2, pick powers density of 56 mW/cm2, 270 mW per pulse with a spot diameter of 2.4 mm, and with repetition rate of 10 Hz for pulse duration of 6 ns. Irradiation was performed during a total time of 2 s in a non-contact mode at a distance of 0.5 mm from implant surfaces. The parameters were chosen according to the results of a theoretical modeling calculation of the Nd:YAG laser fluency on implant surface. Evaluation of contaminants removal showed that the cleaning of the irradiated implant surfaces was statistically similar to those of sterile implants (p-value ≤ 0.05). SEM analysis confirmed that our parameters did not alter the lased surfaces. The increase in temperature generated at lased implant surfaces during cleaning was below 1 °C. According to our findings, Q-switch Nd:YAG laser with short pulse duration in nanoseconds is able to significantly clean contaminated implant surfaces. Irradiation parameters used in our study can be considered safe for periodontal tissue.


1972 ◽  
Vol 50 (4) ◽  
pp. 407-409
Author(s):  
G. L. Busca ◽  
M. Bergeron

A recently introduced technique, the ultrahigh-speed photography of ps light pulses, was used to study the dependence of the pulse duration of a passively Q-switched Nd +3–glass laser on the cavity length and the dye transmission. A constant duration, within the experimental error, was found.


2006 ◽  
Vol 45 (20) ◽  
pp. 4972
Author(s):  
Vladimir A. Berenberg ◽  
Miguel A. Cervantes ◽  
Vladimir S. Terpugov

2017 ◽  
Vol 24 (1&2) ◽  
pp. 177-183
Author(s):  
Le Hoang Hai ◽  
Nguyen Dai Hung ◽  
Hoang Huu Hoa ◽  
Alex V. V. Quema ◽  
Nobuhiko Sarukura

Based on the rate equation set for broadband cavities, the dependence of pulse duration on cavity and pumping parameters is analyzed. The cavity uses a Ce-doped crystal as a gain medium. Computation results show the variation of the pulse width with the change of cavity length, mirror reflectivity, pumping energy and pumping pulse duration. A significant influence of multiple-pulse operation in limiting pulse duration is realized and a pulse-width of the order 200 ps is found to be the limit for the direct generation of ultraviolet single picosecond pulses from a Ce:LLF short cavity.


2021 ◽  
Author(s):  
Zexin Song ◽  
Qi Bian ◽  
Yu Shen ◽  
Keling Gong ◽  
Nan Zong ◽  
...  

Abstract The influence of pumping laser pulse on the property of quasi-continuous-wave diode-side-pumped Nd:YAG laser is investigated theoretically and experimentally here. Under remaining a fixed duty cycle, the average output power increases, and the corresponding thermal focal length shorten with the increase of the pump pulse duration, which attributes to the decrease of the ratio of pulse buildup time to the pulse duration. At a pump power of 146 W, the laser output power changes from 65.1 W to 81.2 W when the pulse duration is adjusted from 150 μs to 1000 μs, confirming a significant enhancement of 24.7%. A laser rate equation model incorporating the amplified spontaneous emission is also utilized and numerically solved, and the simulated results agree well with the experimental data.


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