Chapter 1610 Academician Chang is still conservative

"Academician Wu?" Zhang Runing was startled by Wu Minghan's violent reaction. "What did you see?"

Wu Minghan seemed to have heard nothing and was still immersed in great shock.

After a few seconds, he raised his head and pointed at the eyepiece speechlessly, indicating Zhang Runing to look for himself.

Zhang Runing was full of doubts, but was also very curious.

He immediately replaced Wu Minghan's position and put his eyes closely to the observation port.

Inside the eyepiece, there is deep darkness.

Only the green laser beam has a clearly visible trajectory.

The beam of light angled toward the almost imperceptible flat wafer suspended in the darkness.

then……

At an angle that completely defies common sense, it bends back to the normal line in a direction that is almost symmetrical to the incident light...

Same side!

This...how is this possible? !

"boom!"

The huge shock made Zhang Runing subconsciously raise his head suddenly, and his forehead hit hard on the forehead of Wu Minghan who was also in a petrified state next to him.

Both of them cried out in pain.

But at this moment, this little pain was completely overwhelmed by the shock in my heart.

Zhang Runing didn't bother to rub his forehead, but pressed his eyes back into the eyepiece again!

So weird, watch it again!

dark.

Green light.

Flat wafer.

Light is incident.

Fold to the same side!

Still the same scene.

It’s not an illusion! It’s not an error! It’s a real physical phenomenon!

Zhang Runing raised his head, beads of sweat oozing out of his forehead.

He looked at Wu Minghan, whose expression also changed and his eyes were filled with horror.

The two men's eyes met without words, and they both saw in each other's eyes the same shock that subverted their own cognition.

This seems to violate the law that has dominated the optical world for hundreds of years since Snell's law was established!

But he soon realized that the possibility of Snell's law being wrong was probably very low.

Then... there is only one other explanation left.

Zhang Runing's lips trembled slightly.

A conjecture that only existed at the forefront of theoretical physics popped up in his mind:

"This... this is... negative refraction?!"

His voice was dry, full of questioning and disbelief.

Chang Haonan had been standing calmly by the side, and finally a faint smile appeared on his face, as if everything was under control.

"Yes." He nodded slowly. "This is the macroscopic atomic array material we just successfully prepared, Ga-Ge (0001)."

"It exhibits ... negative refraction properties over a wide wavelength range from visible light to extreme ultraviolet light."

"Om..."

Zhang Runing felt as if his brain was hit by a heavy hammer, and there was a loud roar.

Negative refraction materials!

It actually exists! And it has been prepared, right in front of us!

So, here are some alternative designs for the ArF-1800 objective lens set...

More than just limited reference value?

That's probably a way of taking his feelings into consideration.

We have to start all over again!

……

After the huge shock, the three did not return to the previous meeting room.

Chang Haonan directly took the dizzy Zhang Runing and Wu Minghan to his office.

Then he personally picked up the teapot and poured a cup for Zhang Runing and Wu Minghan respectively:

"You two, have some tea first."

He doesn't have any particular preferences when drinking tea, he just emphasizes that all beings are equal under the boiling water.

The aroma diffused with water vapor, slightly alleviating the aftermath of shock lingering in the air.

Zhang Runing subconsciously wanted to pick up the teacup, but immediately shrank back because of the heat.

As a top expert in optical systems, his brain had begun to work at high speed after recovering from the initial shock.

Academician Zhang Runing did not touch the teacup again, but asked one of the most important questions, "Since this material exhibits the property of negative refractive index, according to theoretical deduction, does it also necessarily have a dispersion property that is completely opposite to that of conventional optical materials?"

After all, he is an expert in the field of optics.

The fact that negative refraction will lead to negative dispersion is something that even a junior high school student can understand.

But it is difficult to realize it at the first time.

Especially in such a shock.

"Researcher Zhang hit the nail on the head," Chang Haonan affirmed.

He picked up the tablet computer on the table, operated it quickly, called up a set of comparison photos, and showed them to the two.

The photos were taken in a darkroom environment.

It is a high-definition remake of the one Chang Haonan tested that day——

On the left is an ordinary crown glass prism. A beam of white light passes through it and disperses the standard rainbow spectrum on the screen - red, orange, yellow, green, cyan, blue, and violet.

Red is on the outside and purple is on the inside.

And on the right is the double negative refractive flat lens they just saw in the basement.

The same beam of white light passes through it, forming a colorful light band on the screen...

The order is exactly the opposite.

"Sure enough..." Zhang Runing and Wu Minghan said almost in unison.

"Perfect! They complement each other perfectly!" The former tapped the table with his fingers excitedly.

As an expert in optical systems, he certainly knew the value of this property in the process of de-dispersion.

Wu Minghan also rubbed his hands excitedly:

“No wonder Academician Chang mentioned lutetium aluminum garnet the other day… With this material, the difficulty of solving chromatic aberration and image aberration problems is greatly reduced!”

Zhang Runing has already thought of a higher level:

"No, no, no, it's not just a matter of chromatic aberration and aberration..."

He dipped his hand in some water and gestured on the coffee table: "It can also simplify the complexity of the objective lens group of the lithography machine, leaving room for improvement in the aperture angle of the entire objective lens group... In this way, we only need to solve one problem of light path obstruction..."

His thoughts became clearer and he became more and more excited as he spoke, to the point where he could hardly sit still.

It seemed as if he was about to get up and rush back to Changguang to start drawing the design in the next second.

However, Chang Haonan was not in a hurry.

The next key point is also raised.

"Researcher Zhang, in the design of the catadioptric system you just mentioned, besides chromatic aberration and aberration, there seems to be another core problem?"

Zhang Runing nodded immediately, frowning slightly: "Yes. That's the problem of light path obstruction."

He picked up a pen and quickly sketched out three sets of simplified catadioptric objective lens diagrams on a piece of paper.

"In a catadioptric system, we use mirrors to fold the light path and reduce the size of the system."

He pointed to the location of the reflector on the sketch:

"For a reflector, the closer the light is to vertical incidence, the more conducive it is to image calibration. However, completely vertical incident light will inevitably lead to the obstruction of the imaging beam between the two reflectors. This is a fundamental contradiction."

Zhang Runing drew a cross on the line representing the light beam.

"To solve this problem, the current mainstream solution is to adopt an off-axis asymmetric field of view design."

"To put it simply, it allows the light beam to pass through the center of the system not symmetrically, but eccentrically and asymmetrically."

“Also, increasing the distance between the reflectors leaves room for the light beam to pass through.”

He sketched out the path of the beam's deflection and the distance between the mirrors.

“But this brings new problems: the asymmetric field of view will cause the system aberrations, especially coma and astigmatism, to increase sharply, which is extremely difficult to correct.”

"At the same time, increasing the mirror spacing will also increase the size of the system, losing the 'compact' advantage of the catadioptric system. It is difficult to find a perfect balance."

Zhang Runing put down his pen, with a hint of helplessness in his tone:

"This is also one of the core bottlenecks in the design of catadioptric objectives."

He looked at Chang Haonan, wanting to hear what the other party had to say.

The mentality is completely different from half an hour ago.

Chang Haonan did not answer immediately, but picked up the sketch and looked at it carefully for a moment.

"The Ga-Ge (0001) material you just saw has another very important property besides its negative refractive index."

He tapped his finger lightly on the "lens" representing the negative refractive material:

"It is a highly anisotropic material ... in terms of its transparency to light of different polarization directions and different incident angles."

Speaking of this, Chang Haonan also felt it was a bit dramatic.

The reason why this thing was made anisotropic in the first place was purely out of helplessness.

Because isotropic negative refractive index materials cannot be made transparent.

As a result, it came in handy.

"That is, by controlling its crystal orientation and surface treatment..."

While he was still organizing his words, Zhang Runing had already thought of the following content:

"Is it possible to make the same lens refract some ranges of incident light and reflect another range of incident light?"

It's easier to talk to smart experts.

Chang Haonan nodded directly: "That's it."

Zhang Runing's voice was trembling: "So... we can design a... hybrid component?"

"Can it act as a negative refractive lens in some areas and a reflective mirror in other areas? Or even induce total internal reflection to change the direction of the light path?"

“And all this can be achieved through the intrinsic properties of materials and design?”

In fact, he was basically sure that his idea was correct.

But it all seemed too good to be true.

If this can be realized, it will not only simplify the design, but completely break away from the framework of the traditional catadioptric and refracting system and almost reconstruct the implementation method of the objective lens group!

"My mind is a little confused now..." Zhang Runing rubbed his forehead, "But from my experience, if this material is introduced, the design difficulty of the catadioptric system... can probably be reduced to a level similar to that of the full refractive system."

He took a deep breath, suppressed the excitement in his heart, and looked at Chang Haonan with unprecedented solemnity and admiration.

"Academician Chang, I withdraw all my previous doubts."

"What you bring is not only new materials, but also a subversive optical design philosophy!"

"I request that a three-party joint attack be launched immediately!"

"The design of ArF-1800 must and will be completely and revolutionary reconstructed based on this!"

"..."

This time, even Wu Minghan couldn't help but interject:

"If you want to merge the refraction system and the catadioptric system, then we at Huaxin International... should be able to provide some help."