Tech_Spec_PR_63-9049-17_final.docx

Technical Specifications PR# 63-9049-17

1.0 SUMMARY

The Naval Research Lab requires a scanning confocal imaging micro-Raman spectroscopy system with a cooled charge-coupled device (CCD) detector that will also perform scanning micro-photoluminescence (PL) and reflectivity spectroscopies over the same user-defined area. The wavelength range of interest is 300 nm to 1100 nm. The system shall allow confocal acquisition and comparison of the Raman, PL and reflectivity spectra from the same user-selected spot, and acquisition and comparison of the Raman, PL and reflectivity images created using vendor-supplied software from the respective spectra over the same user-defined scanned area. The minimum diameter of the analyzed area shall be diffraction limited (less than twice the wavelength of the excitation source). The system must allow the user to input his own laser (or white light) beams so that the PL (reflectivity) can be acquired with a user-provided laser line (broad band light source) different from the vendor-provided Raman source. The system shall provide the ability to circularly polarize the light incident on the sample, and analyze the light emitted / reflected from the sample for circular polarization.

The system shall include all hardware, control electronics, cabling, computer, software, manuals and accessories necessary to meet the following operating and performance specifications. The system will be installed and tested on a standard isolated optical table at NRL. Typical applications include optical characterization of single monolayer materials ( < 1 nm thick) such as graphene or molybdenum disulfide on SiO2 / Si substrates.

2.0 SAMPLE STAGE AND SCAN STAGE

2.1 Sample size

The system shall provide a sample stage(s) that allows data acquisition for a sample up to 100 mm diameter at 300K in the ambient environment, with a maximum sample thickness of 1 mm.

2.2 Motorized Z Sample Stage

· Software-controlled motorized stage for focusing

· Stage travel range: 100 mm or more

· Stage resolution: 10 nm or less

· Minimum step size: 10 nm or less

· Repeatability: 100 nm or less

2.3 Autofocus / Planarization: the instrument shall provide an automated routine to insure that the analyzed spot on the sample surface remains within the focal plane as the sample is scanned along XY during data acquisition.

· One planarization mode shall focus at each spot before data acquisition at that spot

· At least one planarization mode shall determine the plane of the sample surface by establishing focus at 3 or more user defined spots, calculating the angle of the sample surface to the focal plane, and then adjusting the Z stage during the scan so that each analyzed spot in the sample surface is in the focal plane during the XY scan without refocusing at each analyzed spot

2.4 XY Scan Modes

· Single point acquisition:

The instrument shall enable the user to visually identify one or more discrete points on the sample using the microscope, and acquire spectroscopic data from those points for a user defined spot size.

· Scanned acquisition:

The instrument shall provide scanning in the XY plane to acquire data over a user-defined area with a user-defined step size, spot size and dwell time per spot, with the following specifications:

· Size of scanned area: minimum = 5 x 5 um; maximum = 100 x 100 um

· Step size: minimum 100 nm; maximum > 10 um

· Spot size: minimum = twice the incident wavelength; maximum = 100 um

· The instrument shall provide high precision, nano-step size scanning of the sample by rastering the incident laser beam with the sample fixed to provide highest spatial resolution over small areas (~ 50 um x 50 um). All supplied objectives should be compatible with this function.

3.0 OPTICAL ELEMENTS

The instrument shall include the following optical elements:

3.1 Coupling optics (lenses, splitters, mirrors, etc)

All coupling optics shall be high throughput achromatic elements optimized to work from 300 to 1100 nm with maximum efficiency

3.2 Gratings

A grating turret holding at least 2 gratings selectable by the control software. The gratings shall be kinematically mounted and field replaceable by the end user. One grating should be optimal for Raman, , and provide at least 0.047 nm resolution with a wavelength range of about 16 nm when centered at 532 nm. One grating should be optimal for PL, and provide at least 0.68 nm resolution with a wavelength range of about 233 nm when centered at 532 nm.

3.3 Detector

A 1024 x 256 pixel thermoelectric cooled charge-coupled device (CCD) detector suitable for the 300 nm – 1000 nm wavelength range, with a dark current less than 0.0005 electrons / pixel / second, a readout noise less than 5 electrons rms at a scan rate of 20 kHz, and a quantum efficiency of at least 50% over the 400 – 900 nm wavelength range.

3.4 Second detector port

At least one additional port for the optional future addition of a second multichannel detector

3.5 Polarizers

· The system shall include sufficient physical space to include optical elements / hardware that provide the ability to circularly polarize the light from the optical source (user selected positive and negative helicity), and analyze the light emitted / reflected from the sample for positive and negative helicity for the 500-1000 nm wavelength range. Vendor will supply provisions for mounting this hardware. An acceptable provision would be an integrated optical breadboard.

· All vendor supplied optical elements within the instrument shall be linear and circular polarization-preserving.

3.6 Filters

The system shall provide the software selectable ability to insert a particular filter into the optical path both at the excitation source and at the detector.

· For Raman spectroscopy, this shall include a visible half wave plate with computer control for up to 90° rotation of the incoming laser polarization and a Vis analyzer in the form of a linear polarizer with computer control to analyze the Raman signal for the range 400-700nm.

· For Raman, PL and reflectivity spectroscopies, this shall include a series of laser rejection filters. One filter must be appropriate for Raman measurements with a 532 nm source, one must be appropriate for Raman measurements with a 488 nm source, and one must be a broad-band beam splitter. All must be capable of withstanding power densities of at least 1 W/cm2. At least one of these filters must be demountable to allow for user to swap in NRL supplied custom filters.

· For all sources, a sequence of neutral density filters must be available to control the intensity of the incoming laser.

3.7 Light sources

· Raman source: a 532 nm air cooled frequency doubled Nd:Yag laser, 50 mW power, less than 1 MHz bandwidth, with edge and bandpass filters set at 532 nm for measurements from 50 cm-1, with motorized software controlled coupling optics to spectrometer,

· the necessary software controlled motorized coupling optics to inject the beam of an external NRL-supplied visible laser or white light source into the spectrometer and illuminate the same spot on the sample as the vendor supplied laser with a beam diameter twice that of the wavelength or smaller. The external sources include a broad band white light source, and laser lines in the range 488-1100 nm.

4.0 OPTICAL IMAGING

The instrument shall incorporate an optical binocular confocal microscope for visual inspection of the sample and to identify the desired area of analysis. The microscope shall be of the open frame design (alternatively referred to as “free-space” or “open-space” design) to allow a large accessory such as a cryostat to fit under the microscope objective. It shall include optics with 1 um resolution and an integrated color TV camera (3 Mega-pixel with CMOS chip) for optical viewing / still image capture / video capture of the area of the sample to be subsequently studied. This will include optics, camera, multi-level illuminator, software, hardware and viewing screen to provide an optical image / video of at least 3 mega-pixel resolution.

5.0 SOFTWARE

The control software shall provide for complete instrument control, data acquisition and processing. It shall provide for control of:

· Sample position and temperature

· optical viewing / imaging of sample

· Data acquisition, display and storage

· Data processing, analysis, export and presentation

5.1 Data acquisition, display and storage, to include

· operation of Raman laser source

· select spot size and location on sample

· select light source

· select grating

· select filters and polarizers

· define area to be scanned

· define number and location of spots to be analyzed within scanned area

· select scan mode

· acquire spectra

· store spectra

· allow for automatic refocusing of image during sample translation

· image collection via collation of images taken at sequential focal positions

5.2 Data processing, analysis, export and presentation, to include:

· Spectral labeling providing peak positions, intensities, linewidths for raw spectra

· Fitting of spectral features to user-selected or user-defined lineshape (e.g. Lorentzian, Gaussian, etc) and subsequent determination of peak positions, linewidths, separations, intensities (peak and integrated), and specified ratios thereof. One example would be to determine the intensity ratios of the graphene D, G and 2D Raman features; a second example would be to determine the separation of the graphene G and 2D peaks; a third example would be to determine the separation and integrated intensity ratio of feature A to feature B for any spectrum.

· multivariate analysis

· automated location and analysis of particles

· ability to create, store and execute custom processing / analysis sequence

· Directly copy/paste to presentation programs

· Multiple image comparison

· Image overlay of two different images

6.0 FUTURE EXPANSION AND UPGRADEABILITY

System must be field upgradeable, both hardware and software, to add the following modes of operation for a period of at least 2 years after its initial purchase and installation:

· Cooled linear InGaAs array detector of 512 pixels, wavelength range from 800 nm to 1550 nm with a quantum efficiency of 80% between 1000 nm and 1500 nm. Pixel size: 50 μm x 500 μm.

· Ultra-low frequency Raman module

7.0 OPTION PRICING

Vendor should include line item pricing in bid for the following options, which may or may not be included in this purchase.

· Ultra-low frequency Raman module

8.0 INSTALLATION, TESTING, AND ACCEPTANCE

The contractor shall deliver the system to NRL’s building 208 room 203A no later than 4 months after contract award. Installation shall be completed no later than 30 days after delivery. NRL shall provide the necessary facilities and utilities for proper installation and operation, including a vibration isolated optical table. The contractor shall provide operational demonstration including demonstration of all operating modes, user controlled functions, sample insertion, grating change, filter change, data acquisition / manipulation / analysis and export. The system shall be ready for immediate use following installation and set-up. Acceptance shall occur after installation and testing is complete.

9.0 TRAINING

The contractor shall provide at least 16 hours of onsite system training for at least 4 people at the NRL. Training shall occur no later than 30 days after installation, testing and acceptance is complete.

10.0 WARRANTY

The contractor shall provide the standard commercial warranty offered to the general public, including labor and materials. The period of the warranty shall begin upon acceptance of deliverables and last a minimum of 12 months.