Apparatus for reduction of signal variation in sequencing system

A method comprising:

• communicating light through an illumination assembly toward a sequencing stage, the illumination assembly including:
• a light source,
• a first lenslet array interposed between the light source and the sequencing stage,
• a second lenslet array interposed between the light source and the sequencing stage, and
• a diffuser interposed between the light source and the sequencing stage;
• the communicated light being further communicated toward a plurality of reaction sites at the sequencing stage, each reaction site containing a biological sample.

An apparatus, comprising:

• a sequencing stage configured to receive a flow cell comprising a plurality of reaction sites, each reaction site being configured to contain a biological sample;
• and
• an illumination assembly configured to project light toward the sequencing stage to thereby illuminate the reaction sites, the illumination assembly including:
• a light source,
• a first lenslet array interposed between the light source and the sequencing stage, and
• a second lenslet array interposed between the light source and the sequencing stage.