Ultrafast TEM JEOL 2100 (Kista)

Instrumentation

TEM: Modified JEOL JEM 2100

Laser: Amplitude Systemes Tangeringe HP. Average power 35 W. Operational wavelengths 258 nm, 515 nm, and 1030 nm. Pulse length 300 fs. Equipped with SHG and FHG unit.
Holders: Single tilt, double tilt, liquid nitrogen, and biasing.
Detectors: Gatan Ultrascan, ASI CheeTah hybrid pixel detector, Gatan imaging filter Quantum SE, Gatan dark and bright field detectors.

This is TEM is cabable of performing pump-probe spectroscopy together with a fs-laser. The time resolution of the imaging system is <1ps and the spatial resolution is 1nm in imaging mode, and 1Å in diffraction mode.

In a UEM operating in stroboscopic mode a femtosecond laser pulse is steered into a modified column of a TEM and directed onto the cathode to generate a few electrons ultra-short electron pulse through a photoemission process. The femtosecond electron pulse travels through the column to the sample. A second laser pulse (from the same source) is directed through an adjustable optical path towards the sample to initiate the desired change in state (chemical reaction, phase transition, mechanical motion, etc.), thus enabling a temporal reference point (time zero) for the changes that occur. By fine-tuning, at the femtosecond time scale, the relative arrival time of the laser pulse (pump or clocking pulse) and electron pulse (probe pulse), a series of micrographs (or diffraction patterns) can be recorded during the process of change in state and information on many aspects of its dynamic or transient properties can be obtained. The UEM in this design can produce sub nm resolution in microscopic imaging, a precision of a few thousandths of an Ångström in diffraction mode, and  1 eV energy resolution in electron loss spectroscopy or energy filtered imaging. All with a time resolution of a few hundred femtoseconds. This is 10 orders of magnitude better than conventional microscopes, which are limited by the video-camera rate of recording.

The instrument is computer controlled for automatic acquisition of temporal delay scans. For time resolved analysis time slots of less than 12 h is not realistic. A typical experimental session is 3-5 days.

Booking page JEOL JEM-2100

Booking page Ultrafast Transmission Electron Microscope

Main contact person: Jonas Weissenrieder ( jonas@kth.se ).

Location: Isafjordsgatan 22, Kista Electrum Laboratory

Read more about the Ultrafast electron microcopy

Department of Applied Physics, Division of Materials and Nanophysics, www.aphys.kth.se/mnp