1：Experimental Design and Method Selection:

The study involves developing a simple model for the efficiency of exciting a molecule to generate a photon and validating this model through experiments on a single DBT molecule in an anthracene crystal. The theoretical models include rate equations for the steady-state population of the excited state.

2：Sample Selection and Data Sources:

A single DBT molecule in an anthracene crystal is used as the sample. The data sources include measurements of the photon count rate and the second-order correlation function.

3：List of Experimental Equipment and Materials:

The setup includes a confocal microscope, a tuneable titanium sapphire laser, a pulsed diode laser, polarisation maintaining fibre, aspheric lens, half wave plates, polarising beam splitter, neutral density filter, dichroic mirror, beam sampler, galvo mirrors, lenses, microscope objective, avalanche photodiodes, and a closed-cycle cryostat for cooling the sample.

4：Experimental Procedures and Operational Workflow:

The molecule is excited either by a cw tuneable titanium sapphire laser or by a pulsed diode laser. The laser light is coupled to the table through a polarisation maintaining fibre, and the fluorescence from the DBT molecules is collected and analyzed to measure the photon count rate and the second-order correlation function.

5：Data Analysis Methods:

The data is analyzed using rate equations to determine the excited-state population and the efficiency of photon generation. The second-order correlation function is used to confirm the single-photon nature of the source.