![Fig. 2.9 — Optical trapping by two rays](https://i0.wp.com/opticaltweezers.org/wp-content/uploads/2015/11/Fig2_9.png?fit=660%2C332)
Optical forces produced by two light rays impinging on a glass (np = 1.50) sphere immersed in water (nm = 1.33) when they are arranged (a) with a large angle and (b) with a small angle. Only in the first case there is a stable optical trapping position.
Fig. 2.9 — Optical trapping by two rays