ELIAS spectrometer

World’s leading commercial echelle spectrometer series in Littrow configuration with highest spectral resolution – for highly resolving spectral characterization of emission and absorption lines in particular for excimer laser lithography.

  • Intensity dynamics of up to 4 orders
  • Highest spectral resolution (2.5 million-10 million)
  • Very high imaging quality
  • Simple and error-free operation
  • Motorized optomechanics

Setup

The ELIAS Emission Line Analyzing Spectrometers belong to a worldwide unique monochromator series which provide quantitatively high-resolution spectral analysis of narrow linewidth laser profiles with intensity dynamics of up to 4 orders. By applying CCD detectors with a signal-to-noise ratio of up to 40,000, the line profiles can be detected simultaneously within their spectral vicinity. The patented optical design with echelle grating features a nearly diffraction-limited imaging and a sufficiently high linear dispersion to resolve the halfwidths of the lines with 5-10 pixels considering the typical pixel widths of the line-array detector. A 360 mm wide echelle grating within a Littrow arrangement can be used alternatively in a single, double or even quadruple pass ELIAS setup. This allows to work either with an extremely high resolving capability for profile characterization or with a reduced resolving capability but larger inspection range and higher sensitivity. By a 2.5 m off-axis paraboloid and the accompanying anarmophotic magnification optics with a tangential image reproduction scale of 4:1, a camera focal distance of 10 m is attained.
ELIAS optical setup

The ELIAS spectrometers are extremely thermally and mechanically stable. All models are equipped with fully motorized optomechanics for the automatic focusing and positioning of the spectrum on the detector. By applying reflection optics with broadband UV layers, chromatic aberrations are avoided. The light coupling into the spectrometer is realized via SMA fiber or reflection transfer optics.

The supplied operating software Sophi with optional LabVIEW library for complete remote control of the ELIAS allows fully access of all spectrometer-detector functions via graphic user interface. A scan mode provides the sequential measurements of a larger wavelength range, larger than the free spectral range at a time.

Models

The optical design of all ELIAS models is identical with the standard version ELIAS I.

ELIAS I: Standard version of the ELIAS series.

ELIAS II: ELIAS model with much higher spectral resolving capability, fast shutter and high-resolution detector system with improved cooling for advanced time-resolved measurement with significantly higher signal-to-noise ratio.

ELIAS III: Enhanced development of the ELIAS II with integrated retroreflector that allows to use the echelle grating four times. This doubles the spectral resolution of the ELIAS II.

ELIAS LD: Low Dispersion ELIAS model that does not resolve the halfwidths of the lines with 5 to 10 pixels but instead the free spectral range could be trebled without considerably decreasing the spectral resolving capability compared to ELIAS I.

WAVEMETER: ELIAS I model for absolute wavelength determination at 193 nm

ELIAS Portable: Portable ELIAS I model designed with appropriate damping that allows a transport under “rough” conditions without affecting the optical alignment of the spectrometer.

ELIAS VUV: A vacuum-suited ELIAS I model for the analysis of F2 lasers with a wavelength of 157 nm.

Model ELIAS I
ELIAS VUV
ELIAS Portable
ELIAS II ELIAS III ELIAS-LD WAVEMETER
Pass single double double quadruple single double
Wavelength [nm] λsimul [pm] λsimul [pm] λsimul [pm] λsimul [pm] λsimul [pm] λsimul [pm] λsimul [pm]
157 45 14 152 49
193 48 15 16.4 8.4 170 52 50
248 64 20 22.5 11.5 227 71
266 73 25 29.7 15 275 92
532 146 49 59.4 29.9 551 185
766 244 82 92.5 47.5 846 293
1,064 292 98 200 101 626
Wavelength [nm] FWHM [pm] FWHM [pm] FWHM [pm] FWHM [pm] FWHM [pm] FWHM [pm] FWHM [pm]
157 0.254 0.083 0.31 0.10
193 0.283 0.086 0.060 0.022 0.34 0.11 0.34
248 0.376 0.117 0.082 0.032 0.46 0.15
266 0.428 0.147 0.112 0.042 0.55 0.19
532 0.856 0.294 0.225 0.084 1.10 0.37
766 1.400 0.482 0.339 0.130 1.70 0.59
1,064 1.711 0.588 0.450 0.165 1.25

 

Subject to technical changes without notice

Specifications

Optical design echelle monochromator in Littrow configuration
Aperture f/50
Absolute accuracy better than ±5 pm when calibrating with internal Hg lamp
Detector CCD – ELIAS I: 1,024 pixels; ELIAS II/III: 2,048 pixels
Exposure time, min. ELIAS I: 18 ms; ELIAS II/III: 2 ms
Signal-to-noise ratio (SNR) at level 40,000; better 10,000 / 40 dB
Rel. pixel dispersion error 0.2 fm for 193 nm double pass (depends on wavelength)
Dynamic range 16 bit AD conversion, effectively approx. 33,000:1
Light coupling fiber, except for ELIAS VUV (mirror optics)
Wavelength calibration with integrated mercury lamp (253.652 nm)
Computer PC incl. TFT with Microsoft Windows
Software Sophi, LabVIEW library optional
Dimensions without detector (L x W x H) (1,400 x 310 x 250) mm ELIAS I
Weight without detector 50 kg
Features integrated mechanical shutter

 

Subject to technical changes without notice

Spectra

ELIAS I
ELIAS I 193nm slit single spectrumELIAS I laser spectrum @ 193 nm single pass
ELIAS I 193 nm slit double spectrumELIAS I laser spectrum @ 193 nm double pass
ELIAS I Hg single spectrumELIAS I Hg spectrum @ 253 nm single pass
ELIAS I Hg double spectrumELIAS I Hg spectrum @ 253 nm double pass
ELIAS II
ELIAS II 193 nm slit double spectrumELIAS II laser spectrum @ 193 nm double pass
ELIAS II Hg double spectrumELIAS II Hg spectrum @ 253 nm double pass
ELIAS III
ELIAS III 193 nm single spectrumELIAS III laser spectrum @ 193 nm single pass
ELIAS III 193 nm double spectrumELIAS III laser spectrum @ 193 nm double pass
ELIAS III Hg spectrumELIAS III Hg spectrum @ 253 nm

Applications

  • Excimer laser lithography
  • Measuring of the spectral temporal stability of diode lasers, solid state lasers and emission lines of lamps
  • Precise absolute wavelength determination of emission lines
  • LIBS – laser-induced breakdown spectroscopy


Accessories

Fibers

Fibers
Multimode quarz fibers for laser & spectrometer coupling