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Room-temperature subnanosecond waveguide lasers in Nd:YVO 4 Q-switched by phase-change VO 2 : A comparison with 2D materials

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ABSTRACT

We report on room-temperature subnanosecond waveguide laser operation at 1064 nm in a Nd:YVO4 crystal waveguide through Q-switching of phase-change nanomaterial vanadium dioxide (VO2). The unique feature of VO2 nanomaterial from the insulating to metallic phases offers low-saturation-intensity nonlinear absorptions of light for subnanosecond pulse generation. The low-loss waveguide is fabricated by using the femtosecond laser writing with depressed cladding geometry. Under optical pump at 808 nm, efficient pulsed laser has been achieved in the Nd:YVO4 waveguide, reaching minimum pulse duration of 690 ps and maximum output average power of 66.7 mW. To compare the Q-switched laser performances by VO2 saturable absorber with those based on two-dimensional materials, the 1064-nm laser pulses have been realized in the same waveguide platform with either graphene or transition metal dichalcogenide (in this work, WS2) coated mirror. The results on 2D material Q-switched waveguide lasers have shown that the shortest pulses are with 22-ns duration, whilst the maximum output average powers reach ~161.9 mW. This work shows the obvious difference on the lasing properties based on phase-change material and 2D materials, and suggests potential applications of VO2 as low-cost saturable absorber for subnanosecond laser generation.

No MeSH data available.


Related in: MedlinePlus

The pulsed laser properties with different SAMs.The pulse duration (red line) and repetition rate (blue line) of passively Q-switched waveguide laser as functions of launched pump power by using (a) VO2, (b) graphene and (c) WS2 as SAMs at TE polarization, respectively.
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f4: The pulsed laser properties with different SAMs.The pulse duration (red line) and repetition rate (blue line) of passively Q-switched waveguide laser as functions of launched pump power by using (a) VO2, (b) graphene and (c) WS2 as SAMs at TE polarization, respectively.

Mentions: As to further investigate the pulse features of Q-switched waveguide laser based on the different SAMs, the minimum pulse durations as well as the maximum repetition rates and highest peak powers are measured at TE and TM polarization, respectively. For more direct comparison, the performance of Q-switched waveguide lasers in Nd:YVO4 crystal with three different SAMs are listed in Table 1. For brevity, the laser details are only depicted along TE polarization in Figs 4(a), (b) and (c), which demonstrate the dependences of pulse duration (red line) and repetition rate (blue line) as a function of launched power based on VO2, graphene and WS2 SAMs, respectively. With the increase of the pump power, the pulse duration values decrease correspondingly whilst the repetition rates present the uptrend on the whole, which is typical and reasonable for passively Q-switched lasers51. By varying the launched power, the repetition rates are tunable in a range from 0.3 to 2.9 MHz for VO2, 2.0 to 7.8 MHz for graphene and 2.1 to 3.5 MHz for WS2 SAMs, respectively. It is found that graphene based laser pulse has the highest repetition rate and broadest tunable range, which is proportional to single pulse energy and indicates the potential application of communications5253. Simultaneously, the pulse durations turn from 1.57 to 0.69 ns with VO2, 83 to 22 ns with graphene and 141 to 39 ns with WS2 film, respectively, which presents that the laser pulse on account of VO2 SAMs has the shortest pulse duration of 690 ps in the subnanosecond scale with the highest peak power of 33.1 W. According to the following expression


Room-temperature subnanosecond waveguide lasers in Nd:YVO 4 Q-switched by phase-change VO 2 : A comparison with 2D materials
The pulsed laser properties with different SAMs.The pulse duration (red line) and repetition rate (blue line) of passively Q-switched waveguide laser as functions of launched pump power by using (a) VO2, (b) graphene and (c) WS2 as SAMs at TE polarization, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382777&req=5

f4: The pulsed laser properties with different SAMs.The pulse duration (red line) and repetition rate (blue line) of passively Q-switched waveguide laser as functions of launched pump power by using (a) VO2, (b) graphene and (c) WS2 as SAMs at TE polarization, respectively.
Mentions: As to further investigate the pulse features of Q-switched waveguide laser based on the different SAMs, the minimum pulse durations as well as the maximum repetition rates and highest peak powers are measured at TE and TM polarization, respectively. For more direct comparison, the performance of Q-switched waveguide lasers in Nd:YVO4 crystal with three different SAMs are listed in Table 1. For brevity, the laser details are only depicted along TE polarization in Figs 4(a), (b) and (c), which demonstrate the dependences of pulse duration (red line) and repetition rate (blue line) as a function of launched power based on VO2, graphene and WS2 SAMs, respectively. With the increase of the pump power, the pulse duration values decrease correspondingly whilst the repetition rates present the uptrend on the whole, which is typical and reasonable for passively Q-switched lasers51. By varying the launched power, the repetition rates are tunable in a range from 0.3 to 2.9 MHz for VO2, 2.0 to 7.8 MHz for graphene and 2.1 to 3.5 MHz for WS2 SAMs, respectively. It is found that graphene based laser pulse has the highest repetition rate and broadest tunable range, which is proportional to single pulse energy and indicates the potential application of communications5253. Simultaneously, the pulse durations turn from 1.57 to 0.69 ns with VO2, 83 to 22 ns with graphene and 141 to 39 ns with WS2 film, respectively, which presents that the laser pulse on account of VO2 SAMs has the shortest pulse duration of 690 ps in the subnanosecond scale with the highest peak power of 33.1 W. According to the following expression

View Article: PubMed Central - PubMed

ABSTRACT

We report on room-temperature subnanosecond waveguide laser operation at 1064 nm in a Nd:YVO4 crystal waveguide through Q-switching of phase-change nanomaterial vanadium dioxide (VO2). The unique feature of VO2 nanomaterial from the insulating to metallic phases offers low-saturation-intensity nonlinear absorptions of light for subnanosecond pulse generation. The low-loss waveguide is fabricated by using the femtosecond laser writing with depressed cladding geometry. Under optical pump at 808 nm, efficient pulsed laser has been achieved in the Nd:YVO4 waveguide, reaching minimum pulse duration of 690 ps and maximum output average power of 66.7 mW. To compare the Q-switched laser performances by VO2 saturable absorber with those based on two-dimensional materials, the 1064-nm laser pulses have been realized in the same waveguide platform with either graphene or transition metal dichalcogenide (in this work, WS2) coated mirror. The results on 2D material Q-switched waveguide lasers have shown that the shortest pulses are with 22-ns duration, whilst the maximum output average powers reach ~161.9 mW. This work shows the obvious difference on the lasing properties based on phase-change material and 2D materials, and suggests potential applications of VO2 as low-cost saturable absorber for subnanosecond laser generation.

No MeSH data available.


Related in: MedlinePlus