Hidden Heroes: Service to the World - VIDEO

The lives of 7 C.S.J. women who have effected social change through service and action were dramatized. These stories arose from challenged regions of the world, such as El Salvador and Papua New Guinea, as well as the work these women have done on behalf of the homeless, battered women, gangs and other youth at risk, in prisons and juvenile halls, here at home. A reception followed. Special thanks to our Partners, The Ignatians

Silver nanoparticle-film based saturable absorber for passivelyQ-switched erbium-doped fiber laser (EDFL) in ring cavity configuration

We report a passive Q-switched erbium-doped fiber laser based on silver (Ag) nanoparticle thin-film saturable absorber (SA). The thin film was sandwiched between two fiber ferrules, which offer flexibility and easy integration into the ring cavity. Self-started and stable Q-switching is achieved at a central wavelength of 1558.7 nm; within the C-band region. The repetition rate and pulse duration shows a typical Q-switched laser profile as we increase the pump power; the repetition rate increases from 19.471-74.074 kHz while pulse duration decreases from 8.88-3.2 μs. A signal-to-noise ratio value of 35 dB was obtained at 100 mW pump power. By using a balanced twin-detector method, the modulation depth and saturation intensity of the Ag nanoparticle thin film were measured to be 31.6% and 0.54 MW cm-2 respectively. This result offers another alternative to the existing SA materials

Tunable Q-switched erbium-doped fiber laser in the C-band region using nanoparticles (TiO2)

A tunable, passively Q-switched fiber laser using titanium dioxide (TiO2 ) as saturable absorber (SA) is proposed and demonstrated. The TiO2 SA has an insertion loss and modulation depth of 2.6 dB and 19.1 % respectively. The generated laser output has a repetition rate of 83.3 kHz and pulse-width of 0.08 μs at a maximum pump power of 270.0 mW. On the other hand, tuning the operational wavelength from 1534.0 nm to 1570 nm while fixing the pump power at 70.0 mW varies the repetition rate and pulse width from 50.5 to 22.2 kHz and 1.3 to 2.7 μs respectively. The results indicate that TiO2 could be an inexpensive and efficient SA for generating passively Q-switched fiber laser

Tunable Q-switched fiber laser using zinc oxide nanoparticles as a saturable absorber

Nanomaterials have ignited new interest due to their distinctive electronic, mechanical, and optical properties. Zinc oxide nanostructures are fabricated into thin film and then inserted between two fiber ferrules to act as a saturable absorber (SA). The modulation depth and insertion loss of the SA are 5% and 3.5 dB, respectively. When the ZnO-SA is incorporated into the laser cavity, a stable Q-switched pulse tunable from 1536 to 1586 nm (50 nm range) with pulse energy up to 46 nJ was observed. Our result suggests that ZnO is a promising broadband SA to generate passively Q-switched fiber lasers

Ag-nanoparticle as a Q switched device for tunable C-band fiber laser

The use of silver (Ag)-nanoparticle as saturable absorber (SA) to induce tunable Q-switched fiber laser in C-band is demonstrated. The Ag-nanoparticle SA exhibits modulation depth of 31.6% and saturation intensity of 0.54 MW cm−2. The SA is integrated into the laser cavity by sandwiching it between two fiber ferrules. Lasing in CW region starts at 10 mW, whereas stable self-starting Q-switching with a central wavelength of 1558.4 nm begins at 20 mW. As the pump power increases, the repetition rate varies from 10.5 kHz to 24.4 kHz and the narrowest pulse width obtained is around 6.5 µs. The Q-switched laser has a tuning range of 27.3 nm (1552.9–1580.2 nm). The stability of the pulse is verified from the radio-freqeuncy (RF) spectrum with a measured signal-to-noise ratio (SNR) of 46.22 dB. The ability of Ag-nanoparticle as an effective SA may lead to further development of pulsed fiber laser in the field of photonics

Zinc oxide (ZnO) nanoparticles as saturable absorber in passively Q-switched fiber laser

We demonstrate a passively Q-switched erbium-doped fiber laser using zinc oxide (ZnO) nanoparticles thin film as saturable absorber (SA). ZnO exhibits high nonlinear optical response and fast recovery time, fulfilling the requirements of an ideal SA. The nonlinear optical absorption is characterised by modulation depth of 3.5% with saturation intensity of 0.016 MW cm−2. We insert the SA into the laser cavity and obtain stable Q-switched pulse whereby the repetition rate increases from 41.7 kHz to 77.2 kHz while the pulse width decreases from 9.6 μs to 3.0 μs as the pump power is increased from 60 mW to 360 mW. This result suggests that ZnO could be a promising SA for photonic applications

Passively Q-switched erbium-doped fiber laser at C-band region based on WS_2 saturable absorber

We demonstrate a Q-switched erbium-doped fiber laser using tungsten disulfide (WS2) as a saturable absorber. The WS2 is deposited onto fiber ferrules using a drop-casting method. Passive Q-switched pulses operating in the C-band region with a central wavelength of 1560.7 nm are successfully generated by a tunable pulse repetition rate ranging from 27.2 to 84.8 kHz when pump power is increased from 40 to 220 mW. At the same time, the pulse width decreases from a maximum value of 3.84 μs to a minimum value of 1.44 μs. The signal-to-noise ratio gives a stable value of 43.7 dB. The modulation depth and saturation intensity are measured to be 0.99% and 36.2 MW/cm2, respectively