Using sCMOS Cameras for Ultrafast Spectroscopy (SDK)

The Zyla, Marana and iStar sCMOS Spectroscopy features are available on Zyla 4.2 and 5.5 Megapixel camera types with –S suffix and all iStar and Marana sCMOS as standard. A summary of the released feature set is shown below (Table 1).

NOTE: Spectroscopy features on Zyla are supported only with SDK3 & FPGA versions as below.

Table 1 - Spectroscopy feature set

Asymmetric Binning

The sCMOS Spectroscopy feature set allows users to configure any combination of vertical and horizontal binning. This will allow users to avail of full vertical binning for their spectroscopy applications. For horizontal binning the user can select up to 36 horizontally binned pixels. An additional restriction in the horizontal direction means that a user cannot select a horizontal bin number which is greater than ¼ of the AOI width. The binning parameter space is described in table 2.

Table 2 - Table providing example binning range options for different AOI settings

SDK3 Feature Reference

It is typical for a user to configure their required binning options in conjunction with Area of Interest (AOI). Shown below is a list of all AOI features which include vertical and horizontal binning control. Please refer to section 4.6 of the SDK3 Manual for a more detailed description of how to set up AOIs and binning.

User Definable Bit Depth

Standard pixel encoding options on Zyla, Marana and iStar sCMOS are 12-bit (Low Noise) or 12-bit (High Well Capacity) and 16-bit (Low Noise & High Well Capacity). This limits the options for bit depth digitised on head and transmitted over the camera interface. In these configurations the bit depth is optimized to preserve dynamic range for 1x1 binning. However if a user for example chooses 2x2 binning this results in situations where the sum of the pixel count values exceed the maximum digital value transmitted. For example if a user is running in 16-bit mode in 1x1 binning, imaging at half well depth, then a given pixel will transmit 30,000 counts of data per pixel which is below the 16-bit digitization range. If they then select 2x2 binning then the binned superpixel will contain 120,000 counts of data. If the digitization is capped to 16-bit then this super pixel will be saturated at 16-bit (65,536 counts), this means that the dynamic range of the camera is not preserved.

The sCMOS Spectroscopy feature set allows the user to select any bit depth to be transmitted over the camera interface (up to 32-bits) independent of the SimplePreAmpGainControl selection. This allows the user to select any binning combination and still preserve the dynamic range of the camera.

SDK3 Feature Reference

The user can separately define the gain setting through SimplePreAmpGainControl and the transmitted bit depth via PixelEncoding.

Multi-Track Mode

Multi-track mode allows creation of one or more individual acquisition tracks that can be defined (in rows) by the height and position of each track. In this way, the position of the tracks can be adjusted to match a light pattern produced on the sensor, for example by a fibre-optic bundle. Only the sections of the sCMOS image chip that are selected in Multi-track mode are transmitted across to the PC. All the selected tracks are transmitted as a single frame for each acquisition. Users can define up to 256 individual tracks of any height. Each track can be individually set up to have either 1x1 binning or fully vertically binned. Users cannot define the width of the tracks, whether individually or globally – the tracks width is always identical to the full width of the sensor. Figure 1 shows a schematic of the Multi-track mode configurations.

If should be noted that the AOI Height is not settable in Multi-track mode. Instead, the total AOI height and position will be determined by the start position of Track 0 and end position of track N-1 where N is the number of tracks.

SDK3 Feature Reference

Automatic Shutter Output (Zyla and Marana only)

If Automatic shutter control is selected the Aux_Out_2 TTL signal will go high for the duration of an acquisition or acquisition sequence. The user can also define a Shutter Transfer Time which delays the time between the Aux_Out_2 signal going high and the start of the 1st acquisition in an acquisition sequence. Figure 2 shows a timing diagram for Automatic Shutter Output. Table 3 shows the available Shutter Transfer Time range.

Table 3 - Shutter Transfer Time range depending on Sensor Readout Rate

SDK3 Feature Reference

User Configurable External Trigger Delay (Zyla and Marana only)

This feature allows the user, when using external or software trigger modes, to define a delay time between the camera receiving an external trigger and the acquisition start. Table 4 shows a summary of the parameter space for this feature. Note that “Cycle Time” refers to the standard cycle time as can be found in the respective Hardware Guides. 

Table 4 - User Configurable External Trigger Delay parameter space

The granularity of External Trigger Delay control is set to 1 us although it should be noted the jitter between external trigger and exposure start is up to one row readout time. The values of row readout times for different scan speed can be found in the respective Hardware Guides.

SDK3 Feature Reference