Generation of 520 mW pulsed blue light by frequency doubling of an all-fiberized 978 nm Yb-doped fiber laser source
M. Laroche, C. Bartolacci, B. Cadier, H. Gilles, S. Girard, L. Lablonde, and T. Robin
Abstract
Pulsed blue light at 489nm has been generated by second-harmonic-generation of a nanosecond pulsed master oscillator power amplifier system based on a short Yb3+ doped single-mode fiber amplifier at 978nm and an external-cavity diode laser as seed source. The Yb3+-doped fiber was core-pumped by a W type Nd3+ doped doubleclad fiber laser operating on the transition near 930nm (4F3/2 → 4I9/2). 520mW of average power was generated at 489nm using a periodically poled MgO:LiNbO3, corresponding to a conversion efficiency of 34%.
Electronic synchronization of gain-switched laser diode seeded fiber amplifiers
L. Abrardi, T. Feurer
Abstract
We present a hybrid laser system based on all-fiber amplification of a gain-switched laser diode. The diode emits low energy pulses with several tens of picoseconds pulse duration at a wavelength of 1550 nm and a repetition rate of 1 MHz. The three-stage fiber amplifier reaches an overall gain of 55 dB boosting the pulse energy to 0.48 μJ. Much care is taken to preserve an almost bandwidth limited pulse with a spectral width of 0.1 nm and negligible spectral broadening due to nonlinearities. The laser system has been designed such that two or more can be electronically synchronized with the aim to combine them for exploring frequency mixing scenarios. Here, we report first cross-correlation measurements of two synchronized laser systems and present a method to characterize the relative timing-jitter.
11W narrow linewidth laser source at 780nm for laser cooling and manipulation of Rubidium
S. S. Sané, S. Bennetts, J. E. Debs, C. C. N. Kuhn, G. D. McDonald, P. A. Altin, J. D. Close, and N. P. Robins
Abstract
We present a narrow linewidth continuous laser source with over 11 W output power at 780 nm, based on single-pass frequency doubling of an amplified 1560 nm fibre laser with 36% efficiency. This source offers a combination of high power, simplicity, mode quality and stability. Without any active stabilization, the linewidth is measured to be below 10 kHz. The fibre seed is tunable over 60 GHz, which allows access to the D2 transitions in 87Rb and 85Rb, providing a viable high-power source for laser cooling as well as for large-momentum-transfer beamsplitters in atom interferometry. Sources of this type will pave the way for a new generation of high flux, high duty-cycle degenerate quantum gas experiments.
Sensitivity enhancement of fiber-laser-based stimulated Raman scattering microscopy by collinear balanced detection technique
K. Nose, Y. Ozeki, T. Kishi, K. Sumimura, N. Nishizawa, K. Fukui, Y. Kanematsu, and K. Itoh
Abstract
We propose the collinear balanced detection (CBD) technique for noise suppression in fiber laser (FL)-based stimulated Raman scattering (SRS) microscopy. This technique reduces the effect of laser intensity noise at a specific frequency by means of pulse splitting and recombination with a time delay difference. We experimentally confirm that CBD can suppress the intensity noise of second harmonic (SH) of Er-FL pulses by 13dB.The measured noise level including the thermal noise is higher by only 1.4 dB than the shot noise limit. To demonstrate SRS imaging, we use 4-ps SH pulses and 3-ps Yb-FL pulses, which are synchronized subharmonically with a jitter of 227 fs. The effectiveness of the CBD technique is confirmed through SRS imaging of a cultured HeLa cell.
Generation of 43 W of quasi-continuous 780 nm laser light via high-efficiency, single-pass frequency doubling in periodically poled lithium niobate crystals
S. Chiow, T. Kovachy, J. M. Hogan, and M. A. Kasevich
Abstract
We demonstrate high-efficiency frequency doubling of the combined output of two 1560 nm 30 W fiber amplifiers via single pass through periodically poled lithium niobate (PPLN) crystals. The temporal profile of the 780 nm output is controlled by adjusting the relative phase between the seeds of the amplifiers. We obtain a peak power of 34W of 780 nm light by passing the combined output through one PPLN crystal, and a peak power of 43 W by passing through two cascading PPLN crystals. This source provides high optical power, excellent beam quality and spectral purity, and agile frequency and amplitude control in a simple and compact setup, which is ideal for applications such as atom optics using Rb atoms.
Frequency-comb-referenced multi-wavelength profilometry for largely stepped surfaces
S. Hyun, M. Choi, B. J. Chun, S. Kim, S. W. Kim, and Y. J. Kim
Abstract
3-D profiles of discontinuous surfaces patterned with high step structures are measured using four wavelengths generated by phase-locking to the frequency comb of an Er-doped fiber femtosecond laser stabilized to the Rb atomic clock. This frequency-comb-referenced method of multi-wavelength interferometry permits extending the phase non-ambiguity range by a factor of 64,500 while maintaining the sub-wavelength measurement precision of single-wavelength interferometry. Experimental results show a repeatability of 3.13 nm (one-sigma) in measuring step heights of 1800, 500, and 70 μm. The proposed method is accurate enough for the standard calibration of gauge blocks and also fast to be suited for the industrial inspection of microelectronics products.
Narrowband photon pair source for quantum networks
F. Monteiro, a Martin, B. Sanguinetti, H. Zbinden, and R. T. Thew
Abstract
We demonstrate a compact photon pair source based on a periodically poled lithium niobate nonlinear crystal in a short cavity. This approach provides efficient, low-loss, mode selection that is compatible with standard telecommunication networks. Photons with a coherence time of 8.6 ns (116 MHz) are produced and their purity is demonstrated. A source brightness of 134 pairs (s. mW. MHz-1) is reported. The cavity parameters are chosen such that the photon pair modes emitted can be matched to telecom ultra dense wavelength division multiplexing (U-DWDM) channel spacings. The high level of purity and compatibility with standard telecom networks is of great importance for complex quantum communication networks.
N. Bruno, E. Zambrini Cruzeiro, A. Martin, and R. T. Thew
Abstract
We report the realization of a fibred polarization entangled photon-pair source at 1560 nm based on a type-II nonlinear interaction and working in the picosecond regime. By taking advantage of a set of fibre filters, we deterministically separate the photons and project them into wavelength separable states. A standard entanglement measurement with a net interference visibility close to 1 proves the relevance of our approach as an enabling technology for entanglement-based quantum communication.
Distribution of Squeezed States through an Atmospheric Channel
C. Peuntinger, B. Heim, C. R. Müller, C. Gabriel, C. Marquardt, and G. Leuchs
Abstract
Continuous variable quantum states of light are used in quantum information protocols and quantum metrology and known to degrade with loss and added noise. We were able to show the distribution of bright polarization squeezed quantum states of light through an urban freespace channel of 1.6 km length. To measure the squeezed states in this extreme environment, we utilize polarization encoding and a postselection protocol that is taking into account classical side information stemming from the distribution of transmission values. The successful distribution of continuous variable squeezed states is accentuated by a quantum state tomography, allowing for determining the purity of the state.
High-power non linear frequency converted laser diodes fiber laser
O. Jensen, P. Andersen, and A. Hansen
Abstract
We present different methods of generating light in the blue-green spectral range by nonlinear frequency conversion of tapered diode lasers achieving state-of-the-art power levels. In the blue spectral range, we show results using single-pass second harmonic generation (SHG) as well as cavity enhanced sum frequency generation (SFG) with watt-level output powers. SHG and SFG are also demonstrated in the green spectral range as a viable method to generate up to 4 W output power with high efficiency using different configurations.
