Confocal Technology Makes it More Clear
Confocal is an optical technique which can increase the optical resolution and contrast by using a spatial pinhole to block the out-of-focus light. Our confocal technology not only makes the focusing beam spot to close to diffraction limit, but also increases the depth resolution. With a proper XYZ auto stage, u-Raman-EX can be upgraded to Raman imaging or 3D confocal Raman imaging system.
▲Confocal optical path and excitation laser beam spot and profile which can be close to diffraction limit.
Flexible excitation subsystem
The spectral line width is most important for Raman excitation. μ-Raman-HR system used very narrow spectrum combined with good beam quality. It makesμ-Raman system has very good wavenumber range even can be smaller 100 cm-1.
Take our 532nm DPSS laser for example, the spectral line width is small than 0.03nm which is smaller than 0.5 cm-1. Our outstanding narrow-band performance excitation laser make our system to be possible to access to the low frequency Raman region (< 10~200 cm-1)*.
*The low frequency rage have to choose specific optics and configuration as options.
The micro-chamber of μ-Raman system quipped Köhler illumination system with LED light source and digital image camera to capture the optical micro-image and display on LCD monitor.
Users do not need to use traditional eyepiece to watch the micro-image of the microscope, which can reduce fatigue eye membranes and make alignment much easier between excitation beam spot and target sample positions.
Using Olympus BX53 microscope frame with our
micro-chamber provide a highly stable optical stability. The XYZ-scale
adjustment of BX53 makes user to find focus quickly by setting precise and
smooth Z-scale wheel to set the stage height for samples of different sizes or
Single “one-button” for full Raman spectrum
Utilizing high-end scientific array detectors (CCD camera) provide fast multichannel data acquisition for ultimate Raman spectroscopic application.
High sensitivity 95% QE CCD detectors (TE air) and Optimized for Raman spectroscopy
－Back-illuminated CCD, 95% peak QE @ 780 nm
－2000 x 256 active pixels
－15 x 15 um pixel size
－Maximum 142 spectra/ sec
－Ultra-low NIR etaloning
－TE cooling: -60°C at ambient temperature of up to +25°C
－Low-Dark-Current Deep-Depletion (LDC-DD) technology: more Raman bandpass improvement (10 %)
－ Read noise ≦ 6 e-
－ Dark current ≦0.033 e-/pixel/sec
▲QE comparison between Back-illuminated and Front-illuminated CCD sensor
▲The wider (30 mm) Low-Dark-Current Deep-Depletion (LDC-DD) sensor
provides an improved bandpass compared to the traditional (26.6 mm)
Back-Illuminated Deep-Depletion (BI-DD) sensor.
μ-Raman-HR adopts the world’s best Czerny-Turner spectrometer which is intelligent and multi-modal platform for Raman spectroscopy. The spectrometer focal length of μ-Raman-HR is 328 mm with F/4.1 aperture. The toroidal optics enable multi-track fiber detection and excellent sample image relay from a microscope at the grating “0” order. It makes μ-Raman-HR ‘s spectrometer has outstanding astigmatism-corrected optical performance.
Besides the optical design, μ-Raman-HR‘s spectrometer has robust on-axis wavelength drive. This high accuracy direct-drive delivers superb single-grating and grating-to-grating center wavelength repeatability down to 4 pm (0.14 cm-1) and 10 pm (017cm-1) respectively. μ-Raman-HR‘s spectrometer has convenient dual-outputs option which can extend wavelength coverage when combining different wavelength range cameras. The Quad-Turret with RFID is another strength of μ-Raman-HR‘s spectrometer. It can combine up to 4 gratings for much grater flexibility in one single setup. The spectral resolution has more choice of high, medium or low options. At the same time, the grating blaze choices also covers more wavelength range from UV, Visible, NIR to SWIR, which is the benefit to combine photoluminescence spectroscopy with much broad spectral range, compare to other competitor’s max 3-grating spectrometer design. The RFID tags on grating turret ensures automatic recognition and upload of all important turret parameters to the spectrograph.
- Adaptive Focus
To Ensure the best resolution at any wavelength, it adopts a “Adaptive Focus” technology to automated scan the optimized focusing positions when changing between gratings, or cameras. With “Adaptive Focus”, μ-Raman-HR has intelligent and user-friendly interface for uncompromised spectral resolution performance and no need for tedious adjustment of camera potion at the exit ports.
- TruResTM: True spectral resolution enhancement (option)
The spectrometer of system can equip a motorized iris and enhance the spectral resolution which is compatible to a 500 mm focal length spectrometer. This option function is intuitive, rapid and fully user-controlled for greater than 30% true spectral resolution enhancement at the touch of a button. It also enhances the discrimination power of your spectrograph without tedious grating or grating turret chance.
▲Upgradeable to expand to Photoluminescence/ Fluorescence/ Time-resolved-PL
Easy to integrate with different platform
μ-Raman-HR can install microscope cooling and heating stages. One of amazing thing for our cooling/ heating stages is the window-to-sample distance is ≦5 mm which is shorter than many objectives’ working distance and make these stages can directly fit to our microscope stage. The temperature can be controlled through stand-alone controller or software, and the range can be from -196 to 600°C depends on different models.
μ-Raman-HR can equip upright microscope scanning stages. With ranges of
travel from 75x50 mm up to 600x600 mm these systems can also reliably carry out
high precision positioning performances, and make μ-Raman-HR become to confocal Raman imaging system.
a. Laser wavelength: 532 nm (266 nm to 1064 nm is selectable and option)
b. Wavenumber Range: 100 cm-1~4500 cm-1 (extentable; option)
c. Wavenumber Resolution: ≦1.22 cm-1 @ 532 nm (≦0.78 cm-1 @ 632.8 nm)
d. Spatial Resolution: 10 x ≦ 5 um; 50 x ≦ 1 um
e. Detector size 2000 x 256 pixels; working temperature: -60℃*
a. Wavelength: 532.1 nm
b. Output Power: 50 mW (Free space)
c. TEM00 Beam
d. Power stability: <1 % RMS (Free space)
e. Control interface: USB
a. Free space or Fiber input for excitation source
b. Archromatic focusing optics for excitation wavelength (>250 nm)
c. Broadband and high reflectance optics PL signal (From 300 nm to 2500 nm)
d. White light source illumination and sample alignment
e. Mega pixels camera for sample Image and monitoring system
f. Filer wheel for black excitation wavelength
g. Fiber output for spectrometer
a. VIS/NIR 10 X and 50 X objective lens
a. Olyppus BX53 main body
b. Mechanical Stages with Right-Hand Control: X: 76 mm, Y: 52 mm; um resolution
a. Focal length: 328 mm with F/4.1 aperture
b. Adaptive focus for uncompromised spectral resolution performance
c. CCD spectral resolution: 0.1 nm
d. Wavelength accuracy: ± 0.2 nm
e. Max. 4 gratings intechangerable turrent
f. Two exit ports for Raman and PL spectrum
g. Adapter for fiber input on entrance slit
h. USB interface
a. Wavelength range：200-1100 mm
b. Active pixels: 2000 *256
c. Peak QE up to 95% @ 780 nm
d. Pixel size: 15 um x15 um
e. 16 bit A/D converter
f. Read noise: 6 e-
g. Dark current: 0.003 e-/pixel/sec
h. TE cooling
a. Raman/PL mesuremen
b. Spectrum analyis tools (Peak intensity, FWHM, and peak lamda)
c. Laser output power control
d. Automatic filter control
e. HD5 file format
Computer and LCD with Windows system, English version
Flexible & Affordable Confocal Micro-Raman/PL System
－ Multiple laser Selectable; 266 nm~1064nm
－ Fiber-coupling or free space coupling
－ Confocal discrimination
－ Mega-pixel digital image
－ Flexible but rugged design
－ Easy to integrate with different platform
－ Upgradeable to confocal Raman imaging
－Single “one-button” data acquisition for full Raman spectrum
－ Upgradeable to expand to Photoluminescence/ Fluorescence/ Time-resolved-PL
Graphene characterization by Raman spectroscopy
As we know, Raman spectroscopy is very useful for analyzing sp2 and sp3 hybridized carbon atoms. Below is the typical Raman spectrum of graphene, including D-band (~1350 cm-1), G-band (~1583 cm-1 ), D’-band (~1620 cm-1), 2D-band (~2680 cm-1), and D+G-band (~2947 cm-1).
G-band (~1583 cm-1 ) cm-1 : It is common for sp2 carbon system, which is due to the stretching of C-C bond in graphene materials. It is usually used to probe the graphene flat surface.
D-band (~1350 cm-1) and D’-band (~1620 cm-1): They are the disorder levels in sp2-sybridized carbon system. If a graphene sample has a perfect structure, then there is no D-band peak in the Raman spectra.
2D-band (~2680 cm-1): It is used to determine the number of graphene layers. The 2D-band Raman peak shape is much broaden compared to single-layer graphene. For single-layer graphene, the 2D-band is much stronger and sharper.
Multilayer graphene on Si
The sample is fabricated from solution by spin-coating process on Si wafer.
As we can see from the Raman spectrum result, D-band shows there is some disorder structure in this multi-layer graphen structure.
Solution Processed graphite, Raman Spectra and Raman Image
The Raman spectra of solution processed graphite show strong D-band peak which represents the highly disorder inside the sp2-hybridized carbon system.
The optical image with 20x and 50x objectives. With XY mapping stage, the system can do Raman spectra mapping and deliver the Raman peak-image or FWHM-image, which can deliver more detail science from these results.