arXiv subjects

Dallin S. Durfee

Publications and source records attributed to Dallin S. Durfee.

8 recordsLinked to original sources

arXiv2018

Magneto-Optical Trap Field Characterization with the Directional Hanle Effect

We demonstrate the use of spatial emission patterns to measure the magnetic fields used in a magneto-optical trap. The directional aspect of the Hanle effect gives a direct, visual presentation of the magnetic fields, in which brighter fluorescence indicates larger fields. It can be used to determine the direction as well as the magnitude of the field. It is particularly well suited for characterizing and aligning magneto-optical traps, requiring little additional equipment or setup beyond what is ordinarily used in a magneto-optical trap, and being most sensitive to fields of the size typically present in a magneto-optical trap.

physics.atom-ph↗

arXiv2016

Applying Classical Geometry Intuition to Quantum Spin

Using concepts of geometric orthogonality and linear independence, we logically deduce the form of the Pauli spin matrices and the relationships between the three spatially orthogonal basis sets of the spin-1/2 system. Rather than a mathematically rigorous derivation, the relationships are found by forcing expectation values of the different basis states to have the properties we expect of a classical, geometric coordinate system. The process highlights the correspondence of quantum angular momentum with classical notions of geometric orthogonality, even for the inherently non-classical spin-1/2 system. In the process, differences in and connections between geometrical space and Hilbert space are illustrated.

quant-ph↗

arXiv2008

Reflow Soldering of Surface Mount Electronic Components in a Laboratory

We present a basic tutorial for implementing surface mount technology in lab-built scientific instruments. We discuss the advantages and disadvantages of using surface mount chips. We also describe methods for the development and prototyping of surface mount circuitry in home-built electronics. The method of soldering surface mount components in a common toaster oven is described. We provide advice from our own experience in developing this technology, and argue that surface mount technology is often preferable to using leaded components when building large circuits, and is essential if the desired component characteristics are only available in surface mount packages.

physics.ins-det↗

arXiv2008

An Ultra-High Stability, Low-Noise Laser Current Driver with Digital Control

We present a low-noise, high modulation-bandwidth design for a laser current driver with excellent long term stability. The driver improves upon the commonly-used Hall-Libbrecht design. The current driver can be operated remotely by way of a micro-processing unit, which controls the current set point digitally. This allows precise repeatability and improved accuracy and stability. It also allows the driver to be placed near the laser for reduced noise and for lower phase lag when using the modulation input. We present the theory of operation for our driver in detail, and give a thorough characterization of its stability, noise, set point accuracy and repeatability, temperature dependence, transient response, and modulation bandwidth.

physics.ins-det↗

arXiv2006

Numerical calculation of classical and non-classical electrostatic potentials

We present a numerical exercise in which classical and non-classical electrostatic potentials were calculated. The non-classical fields take into account effects due to a possible non-zero photon rest mass. We show that in the limit of small photon rest mass, both the classical and non-classical potential can be found by solving Poisson's equation twice, using the first calculation as a source term in the second calculation. Our results support the assumptions in a recent proposal to use ion interferometry to search for a non-zero photon rest mass.

physics.comp-ph↗

arXiv2005

Increasing the output of a Littman-type laser by use of an intracavity Faraday rotator

We present a new method of external-cavity diode laser grating stabilization which combines the high output power of the Littrow design with the fixed output pointing of the Littman-Metcalf design. Our new approach utilizes a Faraday-effect optical isolator inside the external cavity. Experimental testing and a model which describes the tuning range and optimal tuning parameters of the laser are described. Preliminary testing of this design has resulted in a short-term linewidth of 360 kHz and a side-mode suppression of 37 dB. The laser tunes mode-hop free over 7 GHz and we predict that much larger tuning ranges are possible.

physics.optics↗

arXiv2005

Self-referenced prism deflection measurement schemes with microradian precision

We have demonstrated several inexpensive methods which can be used to measure the deflection angles of prisms with microradian precision. The methods are self-referenced, using various reversals to achieve absolute measurements without the need of a reference prism or any expensive precision components other than the prisms under test. These techniques are based on laser interferometry and have been used in our lab to characterize parallel-plate beamsplitters, penta prisms, right angle prisms, and corner cube reflectors using only components typically available in an optics lab.

physics.optics↗

arXiv2005

A High Temperature Calcium Vapor Cell for Spectroscopy on the 4s^2 1S0 to 4s4p 3P1 Intercombination Line

We have demonstrated a high temperature vapor cell for absorption spectroscopy on the Ca intercombination line. The cell uses a dual chamber design to achieve the high temperatures necessary for an optically dense vapor while avoiding the necessity of high temperature vacuum valves and glass-to-metal seals. We have observed over 50 percent absorption in a single pass through the cell. Although pressure broadening in the cell prevented us from performing saturated-absorption spectroscopy, the broadening resulted in higher signal-to-noise ratios by allowing us to probe the atoms with intensities much greater than the 0.2 uW/cm^2 saturation intensity of the unbroadened transition.

physics.atom-ph↗