Operation and Software Features (Current version: 2.2)

The PicoHarp 300 can be used in various operation modes: 

Integration mode

Measurement of the accumulated events as a function of time, manually started, stopped manually or upon overflow or expiration of a chosen collection time or upon reaching of a defined number of counts. 512 curves with up to 65536 time channels. 

Oscilloscope mode

Repetitive measurement and on-line display, very useful for optical alignment. Flicker free histogram display updates and large rate meters for work in the distance.

Time-Resolved Emission Spectra (TRES)

An optional hardware and software add-on allows to control a monochromator from within the PicoHarp software, allowing automated measurement of Time-Resolved Emission Spectra. This mode drives a monochromator via a stepper motor for collection of spectrally resolved lifetime histograms. Data is collected as in standard Integration Mode and saved in different blocks of memory for each wavelength. Four different monochromator types are currently supported: Sciencetech 9030, Sciencetech 9055, Acton Research SP-2155 and Acton Research SP-275.

Time-Tagged Time-Resolved mode(s) (TTTR) Available as an option

Continuously recording events without onboard histogramming straight to disk. Together with the channel number the arrival time of each event pair with respect to the beginning of the experiment is recorded for ultimate flexibility in offline data analysis, e.g. in single molecule detection and Burst Integrated Fluorescence Lifetime (BIFL) measurement as well as time-resolved FCS or coincidence correlation spectroscopy ("antibunching"). Fast transfer and a large FIFO buffer allow huge count rates without any loss of data. Up to four different external synchronization signals ("markers") can be fed into the data stream and allow to synchronize the data acquisition with external hardware such as scanners for Fluorescence Lifetime Imaging (FLIM).

A real-time correlator is included in the TTTR mode which can be extremely useful in setting up and monitoring of FCS experiments.

Software Overview

The PicoHarp 300 software allows the control of all measurement parameters provided by the PicoHarp 300 module. Both input triggers are programmable for a variety of signal types. All functions of the system are controlled by a software interface for Windows™ 2000/XP or Vista. The software provides functions such as the setting of measurement parameters, display of measurement results, loading and saving of measurement parameters and measurement curves. Important measurement characteristics such as count rate, count maximum and position, and histogram width (FWHM) are displayed continuously. A comprehensive online help function shortens the user's learning curve. Software upgrades for extended functionality will be available with further product development.

A driver library (DLL) for custom Windows™ program development is available as an option and allows to build your own applications e.g. in LabVIEW™ , C++, Delphi™ or Visual Basic™ . Demo code is provided for an easy start. A Linux version is also available for kernel 2.6. The libraries are API compatible, so that applications can easily be ported between the platforms, e.g. using Borland's Kylix/Delphi.

The PicoHarp 300 permits the recording of sub-nanosecond fluorescence lifetimes, extendable to < 10 ps with reconvolution. For multi-exponential reconvolution the FluoFit software is an ideal tool. PicoHarp data can be directly exported via the clipboard.

The figure below shows a screenshot of the operating software with results from a typical fluorescent dye obtained with the PicoHarp 300.

A typical fluorescence decay curve taken with the Pico Harp 300