Photonic lanterns (PLs) are waveguides that convert multi-mode input light to single-mode outputs. Wavefront sensing (WFS) and spectroscopy using a PL have been demonstrated, but PL simulations and experiments show significant mismatches. For the WaveDriver project, a proposed Habitable Worlds Observatory pathfinder that uses a PL for WFS as well as for integral field spectroscopy, we manufactured an optical waveguide consisting of an array of seven 19-port PLs in one device. We present laboratory characterization of the individual PLs, consisting of measurements of the principal modes at each PL input using digital off-axis holography. We compare our mode measurements to simulations to assess the variation in the PL manufacturing process. We discuss expected WFS performance in the WaveDriver configuration.
Photonic lanterns (PLs) are fiber-based waveguides that are capable of focal-plane wavefront sensing while simultaneously directing light to downstream science instruments. The optimal choice of wavefront reconstruction algorithm has yet to be determined, and likely depends on the particular observing scenario under consideration. Previous work in simulation suggests that PLs can be used for nonlinear wavefront sensing for several applications, including sensing the low-wind effect and correcting large-amplitude aberrations. We present the design of muirSEAL (miniature IR SEAL), a testbed designed to test PL wavefront reconstruction over Zernike modes and segmented-mirror offsets. We demonstrate throughput and linear wavefront reconstruction at multiple f-numbers. We further present initial laboratory imaging of a new photonic lantern fabricated at Lawrence Livermore National Laboratory.
Large scale laser facilities are needed to advance the energy frontier in high energy physics and accelerator physics. Laser plasma accelerators are core to advanced accelerator concepts aimed at reaching TeV electron electron colliders. In these facilities, intense laser pulses drive plasmas and are used to accelerate electrons to high energies in remarkably short distances. A laser plasma accelerator could in principle reach high energies with an accelerating length that is 1000 times shorter than in conventional RF based accelerators. Notionally, laser driven particle beam energies could scale beyond state of the art conventional accelerators. LPAs have produced multi GeV electron beams in about 20 cm with relative energy spread of about 2 percent, supported by highly developed laser technology. This validates key elements of the US DOE strategy for such accelerators to enable future colliders but extending best results to date to a TeV collider will require lasers with higher average power. While the per pulse energies envisioned for laser driven colliders are achievable with current lasers, low laser repetition rates limit potential collider luminosity. Applications will require rates of kHz to tens of kHz at Joules of energy and high efficiency, and a collider would require about 100 such stages, a leap from current Hz class LPAs. This represents a challenging 1000 fold increase in laser repetition rates beyond current state of the art. This whitepaper describes current research and outlook for candidate laser systems as well as the accompanying broadband and high damage threshold optics needed for driving future advanced accelerators.
We present a new architecture for quantum-enhanced multiparameter estimation, where measured phases are cascaded along a single optical fiber. Embedded reflectors separate these phases, enabling novel fiber-based quantum distributed sensing of temperature and strain.
We have demonstrated a 173 W, all-fiber multicore amplifier using a six-core single-mode Yb-doped fiber and an all-fiber multi-core pump-signal combiner. Each of Yb-doped cores has 17-µm mode-field diameter and is capable of kW-class operation.
We successfully fabricated a 40-μm core LMA fiber with distributed <40-nm-passband bandpass filter. The stopband is over 300 nm wide with >30 dB/m average suppression. Output M2 is 1.15 at a coil diameter of 25 cm.
We successfully demonstrate Raman combination of fiber lasers in the 1.55-μm regime at the 100-W average power level. We achieved diffraction-limited 4.5-mJ, 2-ns pulses at 20 kHz PRF.
Fiber-based interferometry with entangled photons can provide sub-shot-noise resolution, which is ideal for photon-starved applications. Simulations demonstrate that measurements with realistic losses and other imperfections show quantum-enhanced phase resolution for practical applications.
Building on previous work, we have designed a Nd doped fiber for E-band amplification. Modeling results indicate a fiber design that is applicable to telecom amplifiers.