Generation of Bloch surface beams with arbitrarily designed phases

Area of Science:

• Photonics
• Metamaterials
• Surface Physics

Background:

• Bloch surface waves (BSWs) are electromagnetic surface waves confined to a periodic nanostructure.
• Controlling the phase and propagation of BSWs is crucial for advanced optical applications.
• Existing methods for BSW manipulation are limited in their ability to achieve arbitrary phase control.

Purpose of the Study:

• To propose and demonstrate a new method for arbitrary lateral phase modulation of Bloch surface waves.
• To generate various types of tailored Bloch surface beams using the proposed method.
• To explore the potential of this technique for developing novel optical systems and photonic devices.

Main Methods:

• Utilizing in-plane wave-vector matching to achieve arbitrary lateral phase modulation of BSWs.
• Generating Bloch surface beams via a laser incident on a nanoarray structure on a glass substrate.
• Employing an internal mode as a coupling channel to enhance excitation efficiency.

Main Results:

• Successfully demonstrated arbitrary lateral phase modulation of Bloch surface waves.
• Generated and characterized diverse Bloch surface beams, including subwavelength-focused, self-accelerating Airy, and diffraction-free collimated beams.
• Validated the effectiveness of the internal mode for improved excitation efficiency.

Conclusions:

• The proposed manipulation method offers unprecedented control over Bloch surface waves.
• The generated Bloch surface beams have significant potential for two-dimensional optical systems.
• This work paves the way for advanced lab-on-chip photonic integrations.