Ultra-Sensitive Fiber Spectrometer 200-1100nm | SIMTRUM

Unlike the symmetrical C-T type optical path, the Ultra series spectrometers adopt a unique large numerical aperture optical path design scheme. Under the same volume, Ultra has higher luminous flux and sensitivity. Meanwhile, the Ultra platform boasts excellent thermal stability. Within a wide temperature range, both wavelength drift and spectral peak shape deformation can be effectively suppressed. It is highly suitable for high-precision Raman or fluorescence measurement applications.

Product Feature

For the traditional C-T type optical path spectrometer, its optical path usually includes multiple mirrors and dispersion elements,due to the existence of multiple reflections in the optical path, the loss of the optical signal during propagation is relatively high.The Ultra series spectrometer overcomes the disadvantages of the C-T type optical path through the design of a transmission optical path and a large numerical aperture.

1. Innovative optical design: The large numerical aperture and transmitted optical path design increase the luminous flux, improve the utilization rate, reduce the interference of stray light, and simultaneously lower the optical loss.

2. High optical flux: The large numerical aperture of F/2 can fully coupling the input from 0.22NA fibers, and there is design redundancy, which can be compatible with larger numerical aperture fibers or custom input fibers in the path, achieving more efficient utilization of light energy.

3. Transmitted optical path: Reduces the loss of optical signals through various optical components, effectively maintains light intensity, and achieves high detection sensitivity and detection accuracy.

4. High stability: Within the temperature range of 0 to 40° C, the spectral resolution remains high and unchanged, making it more suitable for industrial applications.

5. Modular design: The optical module of the F/1 series spectrometer is relatively independent of the detector module, supporting quick detector replacement. It can provide a variety of detectors ranging from uncooled to cooled back-illuminated and deep cooled.

6. High light energy utilization rate: It is more suitable for the measurement of fluorescence, Raman and other optical signals. Under the same signal strength, it can accelerate the measurement speed and perform high-speed mapping or multiple average measurements.

Hamamatsu s7031，Suitable for Raman 532/785nm and Ultra VIS

Hamamatsu，G14237-512WA，Suitable for Raman 1064nm

You can refer to the table below to select the wavelength range and resolution you need. For specific details, please contact our sales staff for consultation.

The slit size specifications we can provide are: 25/50/100/200 μm. Generally, the smaller the slit, the narrower the image formed on the detector, and the higher the spectral resolution. However, at the same time, the light flux passing through the slit is less, and the sensitivity of the spectrometer will be lower.

We can offer the grating groove density are: 830/1200/1800 l/mm. Generally, the higher the line density, the stronger the dispersion ability of the grating, the higher the resolution, that is, the narrower the wavelength range that can be detected.

Ultra Raman Selection Reference Table

Ultra VIS Selection Reference Table

In addition to determining the grating specifications, slit sizes and other parameters, you also need to configure optical fibers for your spectrometer to ensure normal operation. The available optical fiber specifications are shown in the following mandatory accessory table.

In addition, we can also provide various related accessories. Customers can choose to purchase them according to their own needs. The list of optional accessories is as follows.

Tab 1. Mandatory Accessories

Optional Accessories

	Integrating Sphere Wavelength 250 - 2500 nm Output port customizable Black anodized aluminum alloy housing		Halogen Light Source Wavelength 360 - 2000 nm SMA905 output connector
	Cuvette Holders  for Abs., Fluo, Raman Use		Optical Mount for Transmittance and Reflectance Sample Measurement
	Sample Holder with Mounting for Transmittance Measurement		Fiber Collimator Wavelength 200 - 2000 nm Numerical aperture 0.22 - 0.37 NA fiber core diameter ≥ 100 µm

Front-illuminated (FI) and back-illuminated (BI) chips are available for selection, allowing users to optimize response characteristics based on specific applications such as ultraviolet-visible light or near-infrared. In addition, the Camera supports custom interfaces (such as Camera Link, GigE), mechanical mounts and optical Windows, facilitating integration into OEM systems or existing experimental platforms.

Features

• 15x15 µm pixel size: Features high dynamic range and resolution
• Cooling temperature -70°C: Minimize noise to the greatest extent
• Low readout noise: Allows the lowest detection limit
• Low dark current: The deep depletion type version enhances the red light response without any dark current loss

Specification

QE curve

1. The E2V Back-Illuminated CCD detector is adopted, providing BI-DD (back-illuminated Deep Depletion) technology. By increasing the thickness of the silicon substrate (>20μm), the quantum efficiency (QE) in the near-infrared band is significantly improved, with a peak QE of up to 95% at a wavelength of 800nm. Within the range of 600-900nm, QE is greater than 80%, and it effectively suppresses red light scattering interference at the same time.

The sensor has a resolution of 2048×264 pixels, with a pixel size of 15μm×15μm. Combined with a large target surface design of 30.7mm×4.0mm, it can cover a wider spectral range at one time, making it particularly suitable for hyperspectral imaging and Raman shift detection.

2. Cooling and Noise Control: Supports -70℃ deep cooling (TEC), reduces dark current to an industry-leading level (< 0.001e -/pixel/s@-70℃) through vacuum sealing technology, and combines readout noise <5e- (@500kHz) to achieve an ultra-high signal-to-noise ratio (SNR) in the near-infrared band, meeting the requirements for weak signal detection.

3. Supports two readout modes:

• Full-resolution mode: Retains the complete details of 2048×264 pixels, suitable for high-resolution spectral analysis;

• Full vertical binning: Superimpose 264 pixel signals in the vertical direction, compress the vertical resolution to 1, and simultaneously increase the signal strength by 264 times, significantly improving the image quality in dark areas. It is suitable for low-light scenes.

The pixel readout rate is 500kHz, compatible with 16-bit digital output, supports internal/external triggering and synchronous TTL signals, and can be seamlessly integrated with external devices such as lasers and spectrometers.

Applicable scenarios

1. Raman spectroscopy: With its high near-infrared QE and low noise characteristics, it can detect weak Raman scattering signals and support technologies such as SERS (Surface-enhanced Raman) and SORS (Spatial Offset Raman), making it suitable for material composition analysis, drug detection, etc.

2. Fluorescence and photoluminescence: In biomedical imaging and semiconductor defect detection, it can precisely capture the weak light signals generated by fluorescent labeling or exciton recombination.

Below, we will compare the light energy utilization rates of the C-T type spectrometer and the Ultra series spectrometer through a simple optical path diagram:

 Schematic diagram of signal coupling between NA=0.22 optical fiber and C-T spectrometer

For the standard common optical fiber with NA=0.22, the divergence Angle of the optical signal is about 25°. However, in the C-T optical fiber spectrometer, the divergence Angle of the signal that can be received by the first mirror is about 20°. At the same time, there is reflection loss when passing through the first mirror, resulting in a relatively low light utilization rate.

 Schematic diagram of signal coupling between NA=0.22 optical fiber and Ultra F/2 spectrometer

For the Ultra series spectrometers, the signal within the divergence Angle (25°) of the NA=0.22 fiber can be fully received, and there is also redundancy (the maximum divergence Angle that the Ultra F/2 series spectrometers can receive is 40°). After passing through the lens group, it directly reaches the grating without going through the mirror, reducing signal loss.

For the design redundancy of the Ultra series spectrometer, we can select a fiber with a larger numerical aperture (NA=0.37) for it. The corresponding divergence Angle of this fiber is approximately 45°. At this time, the divergence Angle that the Ultra F2 series spectrometer can receive is approximately 40°. By further upgrading the optical path, the Ultra F1 spectrometer can be obtained. It can receive a divergence Angle of 60° and can fully receive signals from optical fibers with NA=0.37.

 Schematic diagram of signal coupling between NA=0.37 optical fiber and Ultra F/2 spectrometer

 Schematic diagram of signal coupling between NA=0.37 optical fiber and Ultra F/1 spectrometer

Test Results Comparison

Under the same experimental conditions (same light source, same numerical aperture NA=0.22, same integration time), the light intensity comparison between the Ultra series spectrometer and the C-T type fiber optic spectrometer.

Comparison between Ultra F/2 and C-T type fiber spectrometer

Experimental setup: The Ultra F/2 series spectrometer uses a 150um slit, while the C-T type fiber optic spectrometer uses a 100um slit. Since the slit size is linearly correlated with the light intensity, the equivalent light intensity of the 100um Ultra F/2 is approximately 66% of the green spectrum shown in the figure.

times that of the C-T type spectrometer. That is, the Ultra type spectrometer has higher sensitivity and stronger signal.

Comparison between Ultra F/1 and C-T type fiber spectrometer

Furthermore, we conducted a comparative test on the same halogen tungsten lamp with an integrating sphere using the Ultra F/1 series spectrometer. The measurement results are as follows:

Test results of Ultra F/1 combined with NA=0.39 fiber

The test results of the C-T type fiber spectrometer combined with NA=0.39 fiber

Experimental setup: The Ultra F1 uses a 50um slit, while the C-T fiber optic spectrometer uses a 25um slit. Since the slit size is linearly related to the light intensity, the integration time required for the 25um Ultra F1 to achieve the same light intensity is approximately twice that of the experiment, that is, 20ms.

Under this condition, the sensitivity ratio of Ultra F1 to C-T type fiber optic spectrometer can be equivalent to the inverse ratio of their integration times, that is, 1600ms / 20ms =80 times. It can be seen that when the optical design with a larger numerical aperture and the support of optical fibers with a larger numerical aperture, the advantages of the Ultra system become extremely significant.

The prototype of the optical path structure adopted by the mainstream fiber optic spectrometers/micro-spectrometers on the market is all C-T optical path. Although the C-T optical path has advantages such as small size, stable structure and long equivalent focal length, it also has problems such as low light transmission efficiency and difficult control of imaging quality.

The Ultra series spectrometers adopt a completely different optical path design. Along the direction of the optical path, the incident light passes through a slit and first goes through a lens group for beam expansion and collimation. The collimated parallel light is then projected onto a reflective grating for spectral separation and then enters another lens group to be focused onto the detector. Compared with the C-T optical path spectrometer, the optical path structure of Ultra is simpler and more compact, and the F value of the entire optical path structure has been greatly improved. Therefore, Ultra has higher sensitivity. In addition, Ultra is equipped with a thermoelectric cooled back-illuminated detector, making it an ideal choice for various scientific researches.

Software Interface

Main software user interface 1.Detection Panel  (Function menu and operation buttons) 2.Device Panel (Device list and paremeter settings) 3.Spectral Window (Spectral curve display and spectral window management) 4.Spectral Recording Panel (Spectral curve selection and naming)   Key Spectral processing feature  ● Wavelength Smoothing  ● Defluoresence  ● Substract the background signal ● Rransmission and reflection measurement  ● Absobance measurement  ● Multi measurement with different timing For detail software user manual please Click here

Dimensions

Size diagram of F/2 spectrometer

Q1: A comparison between the Ultra series spectrometer and the symmetrical C-T type optical path spectrometer?

A1:

Q2: Compared with the C-T type fiber optic spectrometer, what are the advantages of the Ultra type spectrometer?

A2: Compared with the traditional reflected optical path, the Ultra spectrometer adopts a transmitted optical path, which can reduce the loss of light passing through and uses an array detector, making it highly suitable for various spectral measurements and featuring high detection sensitivity and accuracy. Meanwhile, the Ultra spectrometer adopts a large numerical aperture optical path design, which enhances the optical utilization rate and reduces the interference of stray light. Suitable for low-light detection.

Q3: What are the differences between cooled detectors and uncooled detectors?

A3: In the spectrometer system, there are significant differences in function and performance between cooled and uncooled detectors.

For cooled detectors, thermoelectric cooling/liquid nitrogen cooling is usually used to reduce the temperature of the detector. Working in a low-temperature environment can significantly reduce thermal noise, improve the signal-to-noise ratio of the system, and thereby enhance the sensitivity and resolution of the spectrum. It is more sensitive to weak signals and is suitable for testing in low-light conditions.

Uncooled detectors do not have additional cooling systems and operate at room temperature or near room temperature. They typically have high noise levels, low sensitivity and signal-to-noise ratios, but are easy to operate and have low maintenance costs.

To sum up: If high sensitivity and low noise are required, a cooled detector is a better choice. If cost and convenience are demanded, a uncooled detector is more suitable.

Q4: What are the differences between back-illuminated and front-illuminated detectors?

A4: Back-illuminated detectors (BSI) and front-illuminated detectors (FSI) are two common types of photodetectors.

The photosensitive area of the back-illuminated detector (BSI) is located at the back of the detector. Light enters through the substrate of the detector and can directly reach the photosensitive material, thereby reducing light scattering and reflection, improving the light reception efficiency, and having a higher quantum efficiency.

The photosensitive surface of the front-illuminated detector (FSI) is located in front of the detector. Light enters through transparent materials, and the circuits and metal layers inside the sensor are in front of the incident light. Due to the obstruction of the circuit structure, some of the incident light will be absorbed and reflected, reducing its receiving efficiency. Moreover, the circuit structure may also introduce more noise.

To sum up: The sensitivity and image quality of back-illuminated detectors (BSI) are usually superior to those of front-illuminated detectors (FSI), and the production cost of front-illuminated detectors (FSI) is more advantageous. The choice of which sensor to use mainly depends on application requirements and budget.

Q5: How to choose the appropriate dynamic range?

A5: The dynamic range of a spectrometer refers to the range of signal strength that the instrument can effectively measure. Under different testing conditions, there are different requirements for the dynamic range of the spectrometer.

When measuring weak light signals (such as the fluorescence signals of biological samples), the sample intensity varies greatly, the mixture is complex, and a wide range of reflectance data needs to be measured. Generally, a high dynamic range of the spectrometer is required to ensure the accuracy of the measurement.

For the spectral analysis of a single component or application scenarios with a small range of signal intensity variation, a low dynamic range spectrometer can be used. In addition, the combined influence of factors such as sensitivity and noise level should be comprehensively considered to select an appropriate spectrometer.

Q6: How to balance the signal-to-noise ratio and sensitivity?

A6: The signal-to-noise ratio (SNR) of a spectrometer is an important performance indicator, representing the ratio of signal strength to noise strength. The higher the signal-to-noise ratio, the better the signal quality and the less noise there is in the interfering signal. Sensitivity usually refers to the ability of a spectrometer to detect signals, that is, the minimum signal strength or concentration it can detect. High sensitivity means that the instrument can accurately identify and measure signals even at low concentrations or weak signals. Under normal circumstances, the higher the signal-to-noise ratio, the more obvious the signal. Compared with background noise, the signal is more prominent. This means that the spectrometer can better distinguish the target signal from the noise, thereby enhancing the sensitivity. Meanwhile, in quantitative analysis, sensitivity is usually related to the detection limit (LOD). LOD is the lowest concentration or signal strength that can be reliably detected. A high signal-to-noise ratio can significantly reduce LOD, thereby enhancing the instrument's sensitivity.

Q7: What are the differences between CCD detectors and CMOS detectors?

A7: Choose a CCD or CMOS spectrometer based on the requirements of sensitivity and speed. If high sensitivity and high-quality imaging are needed, a CCD might be a better choice. If there are higher requirements for speed and cost, CMOS is more suitable.

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