Quantum Cascade Lasers For Spectroscopic Applications. Feasibility And Asset For Muonic-Hydrogen Experiment (original) (raw)
Related papers
Laser spectroscopy of muonic hydrogen
Annalen der Physik, 2013
Muonic hydrogen (μp) is a very sensitive probe of the proton structure. Laser spectroscopy of two 2S-2P transitions in μp was used to determine both the Lamb shift and the hyperfine splitting of the 2S state in μp. The rms charge radius of the proton, R ch = 0.84087(39) fm, was extracted from the Lamb shift. The Zemach radius of the proton, R Z = 1.082(37) fm, was obtained from the 2S-hyperfine splitting. This article summarizes the previously published findings.
The next generation of laser spectroscopy experiments using light muonic atoms
Journal of Physics: Conference Series
Precision spectroscopy of light muonic atoms provides unique information about the atomic and nuclear structure of these systems and thus represents a way to access fundamental interactions, properties and constants. One application comprises the determination of absolute nuclear charge radii with unprecedented accuracy from measurements of the 2S-2P Lamb shift. Here, we review recent results of nuclear charge radii extracted from muonic hydrogen and helium spectroscopy and present experiment proposals to access light muonic atoms with Z ≥ 3. In addition, our approaches towards a precise measurement of the Zemach radii in muonic hydrogen (µp) and helium (µ 3 He +) are discussed. These results will provide new tests of bound-state quantum-electrodynamics in hydrogen-like systems and can be used as benchmarks for nuclear structure theories.
Quantum cascade lasers in chemical physics
Chemical Physics Letters, 2010
In the short space of 15 years since their first demonstration, quantum cascade lasers have become the most useful sources of tunable mid-infrared laser radiation. This Letter describes these developments in laser technology and the burgeoning applications of quantum cascade lasers to infrared spectroscopy. We foresee the potential application of quantum cascade lasers in other areas of chemical physics such as research on helium droplets, in population pumping, and in matrix isolation infrared photochemistry.
Powerful fast triggerable 6 μm laser for the muonic hydrogen 2S-Lamb shift experiment
Optics Communications, 2005
Laser spectroscopy of the 2S-Lamb shift in muonic hydrogen (l À p) is being performed at the Paul Scherrer Institute, Switzerland, to determine the root-mean-square (rms) proton charge radius with 10 À3 precision. A multistage laser system has been developed which provides 0.2 mJ pulse energy tunable at 6 lm wavelength. An excimer pumped dye laser 0030-4018/$ -see front matter Ó is used to drive a titanium sapphire (Ti:Sa) system whose wavelength is then shifted to 6 lm using a multipass Raman cell filled with hydrogen. The short cavity length of the Ti:Sa oscillator (7 cm) guarantees a pulse width of 7 ns and a pulse energy of 1.2 mJ at 708 nm, a wavelength controlled by a mono-mode cw-Ti:Sa laser. The laser is triggered at a maximum 60 s À1 repetition rate by muons entering the apparatus at random times. A new type of multipass cavity has been developed to provide a homogeneously illuminated volume (25 · 7 · 170 mm 3 ).
Laser spectroscopy of the Lamb shift in muonic hydrogen
1999
The muonic hydrogen atom in the 2s state provides the possibility of achieving high precision laser spectroscopy experiments from which a high precision value of the proton radius can be deduced. This will ultimately allow an increased precision in the test of QED in bound systems. Important progress has been made in recent years in the ability to stop muons in a low pressure gas target and in the understanding of the 2s-metastability in muonic hydrogen. As a consequence the 2s-2p laser spectroscopy experiment is now feasible and we present here the basic experimental concept considered by our collaboration.
Laser Spectroscopy of Muonic Atoms and Ions
Laser spectroscopy of the Lamb shift (2S-2P energy difference) in light muonic atoms or ions, in which one negative muon µ − is bound to a nucleus, has been performed. The measurements yield significantly improved values of the root-mean-square charge radii of the nuclei, owing to the large muon mass, which results in a vastly increased muon wave function overlap with the nucleus. The values of the proton and deuteron radii are 10 and 3 times more accurate than the respective CODATA values, but 7 standard deviations smaller. Data on muonic helium-3 and-4 ions is being analyzed and will give new insights. In future, the (magnetic) Zemach radii of the proton and the helium-3 nuclei will be determined from laser spectroscopy of the 1S hyperfine splittings, and the Lamb shifts of muonic Li, Be and B can be used to improve the respective charge radii.
SPIE Proceedings, 2009
The combination of infrared laser spectroscopy with a molecular jet expansion provides a powerful technique to investigate medium sized organic molecules and clusters. The coupling of quantum cascade lasers (QCLs) with two slit jet infrared spectrometers, namely an off-axis cavity enhanced absorption (CEA) spectrometer and a rapid scan spectrometer with an astigmatic multi-pass cell assembly, are described. Two types of QCLs, specifically a continuous wave (cw) liquid nitrogen cooled distributed-feedback QCL at 5.7 µm, and a cw room temperature mode-hop-free external cavity QCL centered at 6.1 µm, were employed as the light sources. A pair of 1 inch highly reflective cavity ring-down mirrors (R = 99.98% at 5.2 µm) separated by 55 cm or a pair of 1.5 inch astigmatic mirrors separated by 20 cm, served as the optical cavities. To automate and to synchronize the timing of the CEA or rapid scan experiments with a pulsed slit jet molecular expansion, two LabVIEW computer programs were developed. For the CEA experiments, one of the cavity mirrors was mounted on a piezoelectric actuator with 1 inch clear aperture to maximize the effective mirror size. The effects of mirror size and laser sweep rate were evaluated. A minimum detection sensitivity of 1.8×10-8 cm-1 was achieved. Jet-cooled molecules were generated using a homemade pulsed slit jet nozzle assembly. A jet-cooled infrared spectrum of methyl lactate was recorded to demonstrate the performance of the CEA spectrometer. Preliminary results obtained with the room temperature QCL coupled to the rapid scan spectrometer are also presented.
Recent advances in quantum cascade laser research and novel applications
Novel In-Plane Semiconductor Lasers II, 2003
Continuous wave (CW) operation of quantum cascade lasers is reported up to a temperature of 312 K. The junction down mounted devices were designed as buried heterostructure lasers with high-reflection coatings on both facets. This resulted in CW operation at an emission wavelength of 9.1 µm with an optical power ranging from 17 mW at 293 K to 3 mW at 312 K. A distributed feedback type device was fabricated and tested as well. It showed CW singlemode operation up to 260 K. These results demonstrate the potential of quantum cascade lasers as CW mid-infrared light sources for high-resolution spectroscopy and free space telecommunication systems.
Laser excitation of the 1s-hyperfine transition in muonic hydrogen
SciPost Physics
The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen (\muμp) with 1 ppm accuracy by means of pulsed laser spectroscopy to determine the two-photon-exchange contribution with 2\times10^{-4}2×10−4 relative accuracy. In the proposed experiment, the \muμp atom undergoes a laser excitation from the singlet hyperfine state to the triplet hyperfine state, {then} is quenched back to the singlet state by an inelastic collision with a H_22 molecule. The resulting increase of kinetic energy after the collisional deexcitation is used as a signature of a successful laser transition between hyperfine states. In this paper, we calculate the combined probability that a \muμp atom initially in the singlet hyperfine state undergoes a laser excitation to the triplet state followed by a collisional-induced deexcitation back to the singlet state. This combined probability has been computed using the optical Bloch equations including the inela...