Three-dimensional micro-/nanofabrication

Photoinitiators for Multiphotonic Absorption Multiphoton three-dimensional micro- and nanofabrication is an emerging technology where a laser beam activates the medium by a multiphoton excitation of the photoinitiator. Conventional one-photon UV sensitive cleavable photoinitiators such as bis-acyl phosphine oxides or benzoin ethers can be activated at 700-900 nm (which is thought to lead to the generation of the same usual initiating radicals) but their two-photon absorption cross sections are rather low. New developments are under way [106-111]. 

Soft lithography is an emerging method for micro- and nanofabrication of two- or three-dimensional structures on surfaces.73 78 This method developed by Whitesides and coworkers uses elastomeric stamps, molds, and conformable photomasks for creating patterns as small as tens of nanometers on substrates. Depending on the... 

Two-photon three-dimensional (3D) micro- and nanofabrication using a femtosecond laser have been used to create various types of 3D micro- and submicrometer structures [70, 74, 260, 265, 574], A microscope with axial (z) and lateral (r) resolutions given by Eqs. (77) and (78) was used for laser microfabrication [574]. Wavelength of irradiation light (/.), refractive index of the material (/ ), and numerical aperture of the objective lens (NA) influence the resolution in axial and lateral directions. 

Chapter 12 focuses on recent advancements in EMM for micro and nanofabrication. It contains various emerging variants of EMM. Various interesting factors of surface structuring of aluminum, stainless steel, and titanium, etc., by EMM have been presented considering not only simple flat surfaces but also complex curved surfaces. EMM can also be successfully utilized for fabrication of three-dimensional nanostructures which has also been reported. 

---