SCM3: 17.5 Tesla Magnet for Ultrafast Optics/ UV/ VIS/ NIR spectroscopy

Superconducting Magnet 3 (SCM3) is a 17.5 tesla superconducting magnet dedicated for optics research and housed in the ultrafast optics user facility, cell 3 of the DC Field Facility. SCM3 is a cold bore system capable of measurements from 4 K to 300 K.

Most of the experiments described below can also be performed in the 25 tesla split magnet.

Below are the capabilities of the ultrafast optics user facility.

Ultrafast and continuous-wave (cw) visible optics

Light Sources

Pulsed sources

ULTRAFAST
Two ultrafast Ti: Sapphire laser cavities:

• Coherent Legend regeneratively amplified laser. The Legend produces 2.5 mJ, 1.55 eV, 130 fs pulses at 1 kHz.
• Coherent Mira 900
  The Mira is capable of cw output and can also be modelocked to obtain 150 fs duration pulses at 76 MHz.

We also have a TOPAS optical parametric amplifier coupled with the Legend to produce ultrafast light covering the UV to the mid-IR (λ ~20 μm).

Q-SWITCHED

• Nd: YAG 1064 nm, 532 nm, 355 nm, 266 nm

CW sources

We have broadband lamps for cw optics, including a tungsten source and a xenon lamp. There are also a few CW lasers:

• HeNe laser (visible) 632.8 nm
• Coherent Innova 307 argon laser (visible and UV) 364 nm, 488 nm, 514 nm
• Kimmon HeCd laser (UV) 325 nm
• Dye laser (visible)

Detectors

CW light detection can be accomplished from the visible to the near-IR using a 0.75 focal length McPherson spectrometer coupled with a Princeton instruments CCD and InGaAs array. We also have a photomultiplier chiller and several PMT tubes capable of covering the same range.

For ultrafast detection, the lab operates a Hamamatsu streak camera (Model C5680) capable of 2 ps time resolution. We have magnetic shielding available to make these measurements compatible with high magnetic field spectroscopy. In addition, the lab has several fast photodiode detectors, as well as a balanced photodiode receiver for sensitive differential detection.

For more information, contact Steve McGill, coordinator for ultrafast and continuous-wave (cw) visible optics.

Infrared spectroscopy

A Bruker Model IFS 113v Fourier transform infrared (FTIR) spectrometer is coupled to SCM3. With a variety of detectors, beamsplitters and light sources, the frequency range of 10-10,000 cm-1 can be covered, with a spectral resolution of as high as 0.03 cm-1. Both transmission and reflection measurements can be carried out in magnetic fields. More detailed specifications are:

• Range: 10,000 to 10 cm-1
• Resolution: Better than 0.03 cm-1
• Sources: SiC glowbar, W lamp and Hg lamp
• Beamsplitters: Ge on KBr, 4 mylar films and CaF2
• Detectors: DTGS with KBr and polyethylene windows, Si bolometer with dewar and preamp, InSb detector with dewar and preamp
• Automation: 3 sources, 4 apertures, 4 filters, 6 beam splitters and 4 detectors
• Sample holders: A cryostat with light pipe and sample changer for transmission measurements and a cryostat with light pipes for reflection measurements may be used in the superconducting and resistive magnets in the Tallahassee facility. Sample temperatures can be controlled between 1.6 K and 100 K. The sample can be angled between 60 and 90 degrees to the field direction. We have recently found that excellent measurements can be made at frequencies up to 3000 cm-1 with the light pipe system.

For more information, contact Jason Li, coordinator for infrared spectroscopy.

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